diff --git a/Source/Modules/ControllerModules/InputState.swift b/Source/Modules/ControllerModules/InputState.swift
index a2cd6052..0b9b5d24 100644
--- a/Source/Modules/ControllerModules/InputState.swift
+++ b/Source/Modules/ControllerModules/InputState.swift
@@ -146,7 +146,7 @@ class InputState {
 
     var attributedString: NSAttributedString {
       let attributedString = NSAttributedString(
-        string: composingBuffer,
+        string: IME.kanjiConversionIfRequired(composingBuffer),
         attributes: [
           .underlineStyle: NSUnderlineStyle.single.rawValue,
           .markedClauseSegment: 0,
@@ -260,7 +260,7 @@ class InputState {
     }
 
     override var attributedString: NSAttributedString {
-      let attributedString = NSMutableAttributedString(string: composingBuffer)
+      let attributedString = NSMutableAttributedString(string: IME.kanjiConversionIfRequired(composingBuffer))
       let end = markedRange.upperBound
 
       attributedString.setAttributes(
diff --git a/Source/Modules/ControllerModules/KeyHandler_Core.swift b/Source/Modules/ControllerModules/KeyHandler_Core.swift
index 604d7845..1cf5db7b 100644
--- a/Source/Modules/ControllerModules/KeyHandler_Core.swift
+++ b/Source/Modules/ControllerModules/KeyHandler_Core.swift
@@ -446,4 +446,19 @@ class KeyHandler {
   func deleteCompositorReadingToTheFrontOfCursor() {
     compositor.deleteReadingToTheFrontOfCursor()
   }
+
+  // MARK: - 其他工具函式
+
+  func kanjiConversionIfRequired(_ text: String) -> String {
+    if inputMode == InputMode.imeModeCHT {
+      switch (mgrPrefs.chineseConversionEnabled, mgrPrefs.shiftJISShinjitaiOutputEnabled) {
+        case (false, true): return vChewingKanjiConverter.cnvTradToJIS(text)
+        case (true, false): return vChewingKanjiConverter.cnvTradToKangXi(text)
+        // 本來這兩個開關不該同時開啟的，但萬一被開啟了的話就這樣處理：
+        case (true, true): return vChewingKanjiConverter.cnvTradToJIS(text)
+        case (false, false): return text
+      }
+    }
+    return text
+  }
 }
diff --git a/Source/Modules/IMEModules/ctlInputMethod.swift b/Source/Modules/IMEModules/ctlInputMethod.swift
index 5a3a4aec..c9d35bd9 100644
--- a/Source/Modules/IMEModules/ctlInputMethod.swift
+++ b/Source/Modules/IMEModules/ctlInputMethod.swift
@@ -298,20 +298,7 @@ extension ctlInputMethod {
 
   /// 遞交組字區內容。
   private func commit(text: String) {
-    func kanjiConversionIfRequired(_ text: String) -> String {
-      if keyHandler.inputMode == InputMode.imeModeCHT {
-        switch (mgrPrefs.chineseConversionEnabled, mgrPrefs.shiftJISShinjitaiOutputEnabled) {
-          case (false, true): return vChewingKanjiConverter.cnvTradToJIS(text)
-          case (true, false): return vChewingKanjiConverter.cnvTradToKangXi(text)
-          // 本來這兩個開關不該同時開啟的，但萬一被開啟了的話就這樣處理：
-          case (true, true): return vChewingKanjiConverter.cnvTradToJIS(text)
-          case (false, false): return text
-        }
-      }
-      return text
-    }
-
-    let buffer = kanjiConversionIfRequired(text)
+    let buffer = keyHandler.kanjiConversionIfRequired(text)
     if buffer.isEmpty {
       return
     }