diff --git a/src/lib/markdown/internalLinkEmbedder.ts b/src/lib/markdown/internalLinkEmbedder.ts
index 467f68b44..5e43c364b 100644
--- a/src/lib/markdown/internalLinkEmbedder.ts
+++ b/src/lib/markdown/internalLinkEmbedder.ts
@@ -4,15 +4,13 @@
 
 // URLの一部になっているときは置換しない (URLの正規表現は完全ではない)
 const urlRegexStr = '(?:https?://)?(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]+(?:/[^/]+)*/?'
+const urlStartRegex = new RegExp(`^${urlRegexStr}`)
 const mentionRegex = new RegExp(
-  `(?<!${urlRegexStr}):?[@＠]([^\\s@＠.]{0,31}[^\\s@＠:.])\\.?`,
+  `(${urlRegexStr})?:?[@＠]([^\\s@＠.]{0,31}[^\\s@＠:.])\\.?`,
   'g'
 )
 const userStartsRegex = /^[@＠]([a-zA-Z0-9_-]{1,32})/g
-const channelRegex = new RegExp(
-  `(?<!${urlRegexStr})[#＃]([a-zA-Z0-9_/-]+)`,
-  'g'
-)
+const channelRegex = new RegExp(`(${urlRegexStr})?[#＃]([a-zA-Z0-9_/-]+)`, 'g')
 
 const backQuote = '`'
 const dollar = '$'
@@ -122,6 +120,8 @@ const replaceAll = (m: string, getters: Readonly<ReplaceGetters>) => {
 
 const replaceMention = (m: string, getters: Readonly<UserAndGroupGetters>) => {
   return m.replace(mentionRegex, s => {
+    const urlStart = s.match(urlStartRegex)
+    if (urlStart && urlStart.length !== 0) return s
     // 始まりが:なものを除外
     if (s.startsWith(':')) return s
     // 終わりが.のものを除外
@@ -155,6 +155,8 @@ const replaceMention = (m: string, getters: Readonly<UserAndGroupGetters>) => {
 
 const replaceChannel = (m: string, getter: Readonly<ChannelGetter>) => {
   return m.replace(channelRegex, s => {
+    const urlStart = s.match(urlStartRegex)
+    if (urlStart && urlStart.length !== 0) return s
     // .slice(1)は先頭の#を消すため
     // 小文字化はgetter内で行う
     const t = s.slice(1)