diff --git a/docs/en/api/speaker.md b/docs/en/api/speaker.md
index 3b6dad4d..9cb02dec 100644
--- a/docs/en/api/speaker.md
+++ b/docs/en/api/speaker.md
@@ -46,7 +46,7 @@ None
 **Description: Set the pitch of speaker.**
 
 | Param | Description | type |
-| --- | --- | -- |
+| --- | --- | --- |
 | freq  | frequency | uint16_t |
 | duration | duration (unit: millisecond) | uint16_t |
 
@@ -71,7 +71,7 @@ Set the beep sound.
 <mark>setBeep(uint16_t freq, uint16_t duration);</mark>
 
 | Argument | Description | Type |
-| --- | --- |-|
+| --- | --- | --- |
 | freq | pitch (frequency Hz) | uint16_t |
 | duration | beep time (ms), optional. | uint16_t |
 
diff --git a/docs/ja/api/speaker.md b/docs/ja/api/speaker.md
index 3ab48aa6..5b1a786b 100644
--- a/docs/ja/api/speaker.md
+++ b/docs/ja/api/speaker.md
@@ -47,7 +47,7 @@
 <mark>tone(uint16_t freq, [uint32_t duration]);</mark>
 
 | 引数 | 説明 | 型 |
-| --- | --- | -- |
+| --- | --- | --- |
 | freq | 音の高さ（周波数Hz） | uint16_t |
 | duration | 鳴動時間 (ms)、 省略可能。 | uint16_t |
 
@@ -73,7 +73,7 @@ Beepで鳴らす音を設定します。
 <mark>setBeep(uint16_t freq, uint16_t duration);</mark>
 
 | 引数 | 説明 | 型 |
-| --- | --- | -- |
+| --- | --- | --- |
 | freq | 音の高さ（周波数Hz） | uint16_t |
 | duration | 鳴動時間 (ms)、 省略可能。 | uint16_t |
 
diff --git a/docs/zh_CN/api/speaker.md b/docs/zh_CN/api/speaker.md
index 79b0c9a5..75cb205c 100644
--- a/docs/zh_CN/api/speaker.md
+++ b/docs/zh_CN/api/speaker.md
@@ -88,7 +88,7 @@ Set the beep sound.
 <mark>setBeep(uint16_t freq, uint16_t duration);</mark>
 
 | 参数 |描述 | 型 | 
-| --- | --- |-|
+| --- | --- |---|
 | freq | 声音频率 (Hz) | uint16_t |
 | duration | 持续时间 (单位：毫秒)  | uint16_t |