An electric toothbrush having an improved coupling structure between a drive shaft and a handle or brush is provided. A drive unit driven by a motor rotates in opposite directions to expose first and second drive shafts, and the drive shaft and first and second coupling units are coupled to each other. A first and second toothbrush handle for transmitting the rotational force and forward / backward motion of the drive shaft, and a brush for brushing teeth by the rotational force and the forward / backward motion provided at the end of the handle； A handle of a third toothbrush having an auxiliary brush coupled to the third drive shaft of the drive unit and rotated at a predetermined angle to polish the occlusal surface of the tooth is provided. Since the toothbrush handle can be attached and detached, replacement by wear of the brush is easy, and the contact force between the brush and the tooth is increased by the elastic force of the cover member covering the handle and the brush. Moreover, when brushing both surfaces of a tooth with two brushes, each brush is applied side by side with a tooth and uniform cleaning is performed, and the product power of the electric toothbrush is improved. [Selection] Figure 1【課題】駆動軸と柄またはブラシの結合構造が改善された電動歯ブラシを提供する。【解決手段】モータにより駆動される駆動ユニットにより相互逆方向に回転し各々前後進する第１、第２駆動軸が露出するケースと、該駆動軸と第１、第２結合ユニットにより各々結合され該駆動軸の回転力と前後進モーションを伝達する第１、第２歯ブラシの柄と、該柄の端部に設けられ該柄に伝達される回転力と前後進モーションにより歯を磨くブラシと、駆動ユニットの第３駆動軸に結合され所定角度で回転され歯の咬合面を磨く補助ブラシを有する第３歯ブラシの柄を備える。歯ブラシの柄の着脱が可能なためブラシの摩耗による交換が容易で、柄とブラシをカバーするカバー部材の弾性力によりブラシと歯との接触力が高まる。また、２つのブラシにより歯の両面を磨くとき各ブラシが歯と並んで当てられ均一な洗浄が行われ、電動歯ブラシの商品力が向上する。【選択図】 図１
