An electric toothbrush is disclosed. The electric toothbrush according to some example embodiments includes a bristle-vibrating unit that vibrates toothbrush bristles to clean a side of teeth in contact with the toothbrush bristles, a bristle direction-sensing unit detecting a direction to which the toothbrush bristles are directed in an oral cavity and a control unit automatically controlling the bristle-vibrating unit in response to the detected direction such that the vibration intensity of the toothbrush bristles when an occlusal side is brushed is weaker than the vibration intensity when a buccal side or a lingual side is brushed.