diff --git a/app/src/main/java/jp/juggler/subwaytooter/api/entity/TootAccount.kt b/app/src/main/java/jp/juggler/subwaytooter/api/entity/TootAccount.kt
index fb72bfab..dbac290f 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/api/entity/TootAccount.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/api/entity/TootAccount.kt
@@ -138,10 +138,10 @@ open class TootAccount(parser : TootParser, src : JsonObject) {
 			
 			this.apiHost = src.string("host")?.let { Host.parse(it) }
 				?: parser.apiHost
-				?: error("missing host")
-
+					?: error("missing host")
+			
 			this.url = "https://${apiHost.ascii}/@$username"
-
+			
 			this.apDomain = apiHost // FIXME apiHostとapDomainが異なる場合はMisskeyだとどうなの…？
 			
 			@Suppress("LeakingThis")
@@ -175,7 +175,7 @@ open class TootAccount(parser : TootParser, src : JsonObject) {
 			
 			this.id = EntityId.mayDefault(src.string("id"))
 			
-
+			
 			this.followers_count = src.long("followersCount") ?: - 1L
 			this.following_count = src.long("followingCount") ?: - 1L
 			this.statuses_count = src.long("notesCount") ?: - 1L
@@ -264,7 +264,7 @@ open class TootAccount(parser : TootParser, src : JsonObject) {
 					
 					val tmpAcct = src.stringOrThrow("acct")
 					
-					val(apiHost,apDomain) = findHostFromUrl(tmpAcct, parser.linkHelper, url)
+					val (apiHost, apDomain) = findHostFromUrl(tmpAcct, parser.linkHelper, url)
 					apiHost ?: error("can't get apiHost from acct or url")
 					apDomain ?: error("can't get apDomain from acct or url")
 					this.apiHost = apiHost
@@ -292,7 +292,7 @@ open class TootAccount(parser : TootParser, src : JsonObject) {
 					
 					val tmpAcct = src.stringOrThrow("acct")
 					
-					val(apiHost,apDomain) = findHostFromUrl(tmpAcct, null, url)
+					val (apiHost, apDomain) = findHostFromUrl(tmpAcct, null, url)
 					apiHost ?: error("can't get apiHost from acct or url")
 					apDomain ?: error("can't get apDomain from acct or url")
 					this.apiHost = apiHost
@@ -317,7 +317,7 @@ open class TootAccount(parser : TootParser, src : JsonObject) {
 					this.id = EntityId.mayDefault(src.string("id"))
 					
 					// MSPはLTLの情報しか持ってないのでacctは常にホスト名部分を持たない
-					val(apiHost,apDomain) = findHostFromUrl(null,null, url)
+					val (apiHost, apDomain) = findHostFromUrl(null, null, url)
 					apiHost ?: error("can't get apiHost from acct or url")
 					apDomain ?: error("can't get apDomain from acct or url")
 					
@@ -347,6 +347,7 @@ open class TootAccount(parser : TootParser, src : JsonObject) {
 	}
 	
 	class Source(src : JsonObject) {
+		
 		// デフォルト公開範囲
 		val privacy : String?
 		
@@ -458,7 +459,8 @@ open class TootAccount(parser : TootParser, src : JsonObject) {
 					decodeEmoji = true,
 					emojiMapProfile = profile_emojis,
 					emojiMapCustom = custom_emojis,
-					unwrapEmojiImageTag = true
+					unwrapEmojiImageTag = true,
+					mentionDefaultDomain = apDomain,
 				).decodeHTML(note)
 					.replaceAllEx(reNoteLineFeed, " ")
 					.trimEx()
@@ -486,6 +488,7 @@ open class TootAccount(parser : TootParser, src : JsonObject) {
 	}
 	
 	companion object {
+		
 		private val log = LogCategory("TootAccount")
 		
 		internal val reWhitespace = "[\\s\\t\\x0d\\x0a]+".asciiPattern()
@@ -544,7 +547,7 @@ open class TootAccount(parser : TootParser, src : JsonObject) {
 		// MisskeyのMFMはIDNをサポートしていない
 		private val reMisskeyMentionBase = """@(\w+(?:[\w-]*\w)?)(?:@($reMisskeyHost))?"""
 			.asciiPattern()
-
+		
 		// MFMパース時に使う
 		internal val reMisskeyMentionMFM = """\A$reMisskeyMentionBase"""
 			.asciiPattern()
@@ -597,34 +600,37 @@ open class TootAccount(parser : TootParser, src : JsonObject) {
 			}
 		}
 		
-		
-		private fun findApDomain(acctArg : String?, linkHelper : LinkHelper?):Host?{
+		private fun findApDomain(acctArg : String?, linkHelper : LinkHelper?) : Host? {
 			// acctから調べる
 			if(acctArg != null) {
 				val acct = Acct.parse(acctArg)
 				if(acct.host != null) return acct.host
 			}
-
+			
 			// Acctはnullか、hostを含まない
 			if(linkHelper != null) return linkHelper.apDomain
 			
 			return null
 		}
 		
-		private fun findApiHost( url:String?):Host?{
+		private fun findApiHost(url : String?) : Host? {
 			// URLから調べる
 			// たぶんどんなURLでもauthorityの部分にホスト名が来るだろう(慢心)
 			url.mayUri()?.authority?.notEmpty()?.let { return Host.parse(it) }
-
+			
 			log.e("findApiHost: can't parse host from URL $url")
 			return null
 		}
 		
 		// Tootsearch用。URLやUriを使ってアカウントのインスタンス名を調べる
-		fun findHostFromUrl(acctArg : String?, linkHelper : LinkHelper?, url : String?) : Pair<Host?,Host?> {
-			val apDomain = findApDomain(acctArg,linkHelper)
+		fun findHostFromUrl(
+			acctArg : String?,
+			linkHelper : LinkHelper?,
+			url : String?
+		) : Pair<Host?, Host?> {
+			val apDomain = findApDomain(acctArg, linkHelper)
 			val apiHost = findApiHost(url)
-			return Pair( apiHost?: apDomain, apDomain ?: apiHost )
+			return Pair(apiHost ?: apDomain, apDomain ?: apiHost)
 		}
 		
 		fun parseFields(src : JsonArray?) : ArrayList<Field>? {
diff --git a/app/src/main/java/jp/juggler/subwaytooter/api/entity/TootAccountRef.kt b/app/src/main/java/jp/juggler/subwaytooter/api/entity/TootAccountRef.kt
index f37e6c1c..b6a056d1 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/api/entity/TootAccountRef.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/api/entity/TootAccountRef.kt
@@ -26,7 +26,8 @@ class TootAccountRef(parser: TootParser, account:TootAccount) : TimelineItem() {
 			decodeEmoji = true,
 			emojiMapProfile = account.profile_emojis,
 			emojiMapCustom = account.custom_emojis,
-			unwrapEmojiImageTag = true
+			unwrapEmojiImageTag = true,
+			mentionDefaultDomain = account.apDomain,
 		).decodeHTML(account.note)
 	}
 	
diff --git a/app/src/main/java/jp/juggler/subwaytooter/util/DecodeOptions.kt b/app/src/main/java/jp/juggler/subwaytooter/util/DecodeOptions.kt
index 3ccab06c..b13d1b39 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/util/DecodeOptions.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/util/DecodeOptions.kt
@@ -4,10 +4,7 @@ import android.content.Context
 import android.text.Spannable
 import android.text.SpannableStringBuilder
 import android.text.style.ReplacementSpan
-import jp.juggler.subwaytooter.api.entity.CustomEmoji
-import jp.juggler.subwaytooter.api.entity.NicoProfileEmoji
-import jp.juggler.subwaytooter.api.entity.TootAttachmentLike
-import jp.juggler.subwaytooter.api.entity.TootMention
+import jp.juggler.subwaytooter.api.entity.*
 import jp.juggler.subwaytooter.table.HighlightWord
 import jp.juggler.util.WordTrieTree
 import java.util.*
@@ -27,7 +24,9 @@ class DecodeOptions(
 	var enlargeEmoji : Float = 1f,
 	var forceHtml : Boolean = false, // force use HTML instead of Misskey Markdown
 	var mentionFullAcct : Boolean = false,
-	var mentions : ArrayList<TootMention>? = null
+	var mentions : ArrayList<TootMention>? = null,
+	// Account.note などmentionsがない状況でメンションリンクをfull acct化するにはアカウント等からapDomainを補う必要がある
+	var mentionDefaultDomain : Host? = null,
 ) {
 	
 	internal fun isMediaAttachment(url : String?) : Boolean {
diff --git a/app/src/main/java/jp/juggler/subwaytooter/util/HTMLDecoder.kt b/app/src/main/java/jp/juggler/subwaytooter/util/HTMLDecoder.kt
index 0957c3b0..e3c90acb 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/util/HTMLDecoder.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/util/HTMLDecoder.kt
@@ -607,8 +607,15 @@ object HTMLDecoder {
 				
 				// Account.note does not have mentions metadata.
 				// fallback to resolve acct by mention URL.
-				val rawAcct = mention?.acct ?: Acct.parse(originalCaption.toString().substring(1))
-				val fullAcct = getFullAcctOrNull(options.linkHelper, rawAcct, href)
+				val rawAcct = mention?.acct
+					?: Acct.parse(originalCaption.toString().substring(1))
+
+				val fullAcct = getFullAcctOrNull(
+					options.linkHelper,
+					rawAcct,
+					href,
+					mentionDefaultDomain = options.mentionDefaultDomain
+				)
 				
 				if(fullAcct != null) {
 					
diff --git a/app/src/main/java/jp/juggler/subwaytooter/util/LinkHelper.kt b/app/src/main/java/jp/juggler/subwaytooter/util/LinkHelper.kt
index fbd974b9..f25eab84 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/util/LinkHelper.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/util/LinkHelper.kt
@@ -3,8 +3,10 @@ package jp.juggler.subwaytooter.util
 import jp.juggler.subwaytooter.api.entity.Acct
 import jp.juggler.subwaytooter.api.entity.Host
 import jp.juggler.subwaytooter.api.entity.TootAccount
+import jp.juggler.subwaytooter.api.entity.TootMention
 import jp.juggler.subwaytooter.table.SavedAccount
 import jp.juggler.util.groupEx
+import java.util.ArrayList
 
 interface LinkHelper {
 	
@@ -104,16 +106,21 @@ fun getFullAcctOrNull(
 fun getFullAcctOrNull(
 	linkHelper : LinkHelper?,
 	src : Acct,
-	url : String
+	url : String,
+	mentionDefaultDomain: Host? = null
 ) : Acct? {
 	
 	// 既にFull Acctだった
 	if(src.host != null) return src
 	
-	val apDomain = linkHelper?.apDomain
+	// Account.noteなどメンション情報が含まれない場合、デフォルトのドメインは投稿者のドメインである
+	if(mentionDefaultDomain!=null){
+		return src.followHost( mentionDefaultDomain)
+	}
 	
 	// トゥート検索等でないならアクセス元ホストを補って良いはず
-	if(linkHelper is SavedAccount && ! linkHelper.isNA && apDomain != null) {
+	val apDomain = linkHelper?.apDomain
+	if(apDomain != null && linkHelper is SavedAccount && ! linkHelper.isNA ) {
 		return Acct.parse(src.username, apDomain)
 	}
 	
diff --git a/app/src/main/java/jp/juggler/subwaytooter/util/MisskeyMarkdownDecoder.kt b/app/src/main/java/jp/juggler/subwaytooter/util/MisskeyMarkdownDecoder.kt
index f17836c8..e7ba8314 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/util/MisskeyMarkdownDecoder.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/util/MisskeyMarkdownDecoder.kt
@@ -831,6 +831,7 @@ object MisskeyMarkdownDecoder {
 		) {
 			// ユーザが記述したacct
 			val rawAcct = Acct.parse(username, strHost)
+				.followHost(options.mentionDefaultDomain)
 			
 			val linkHelper = linkHelper
 			if(linkHelper == null) {
diff --git a/app/src/main/java/jp/juggler/subwaytooter/util/TootTextEncoder.kt b/app/src/main/java/jp/juggler/subwaytooter/util/TootTextEncoder.kt
index 31fb7ba7..e98e3b76 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/util/TootTextEncoder.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/util/TootTextEncoder.kt
@@ -11,6 +11,7 @@ import jp.juggler.subwaytooter.table.SavedAccount
 import java.util.*
 
 object TootTextEncoder {
+	
 	private fun StringBuilder.addAfterLine(text : CharSequence) {
 		if(isNotEmpty() && this[length - 1] != '\n') {
 			append('\n')
@@ -268,7 +269,13 @@ object TootTextEncoder {
 		
 		sb.addAfterLine("\n")
 		
-		sb.append(DecodeOptions(context, access_info).decodeHTML(who.note))
+		sb.append(
+			DecodeOptions(
+				context,
+				access_info,
+				mentionDefaultDomain = who.apDomain
+			).decodeHTML(who.note)
+		)
 		
 		sb.addAfterLine("\n")
 		
@@ -294,7 +301,7 @@ object TootTextEncoder {
 		addHeader(context, sb, R.string.send_header_account_created_at, who.created_at)
 		addHeader(context, sb, R.string.send_header_account_statuses_count, who.statuses_count)
 		
-		if(! Pref.bpHideFollowCount( App1.getAppState(context).pref)) {
+		if(! Pref.bpHideFollowCount(App1.getAppState(context).pref)) {
 			addHeader(
 				context,
 				sb,