The invention relates to an electric
toothbrush capable of automatically adjusting frequency. The electric
toothbrush comprises a fixing cylinder, wherein a fixing groove is formed in the inner wall,close to the top end, of the fixing cylinder, a transmission rod is fixed to the fixing groove through a
rubber ring, a
vibration motor is fixed to the inner wall of one end, close to the fixing cylinder, of the transmission rod, and a fixing disc is arranged on the inner wall of the transmission rod; a
brush head is connected to the center of the fixing disc through a connecting rod in insertingconnection; a rotating hole is formed in the center of one end, close to the connecting rod, of the
brush head, a rolling ball is mounted in the rotating hole, a sliding groove is formed in the innerwall of the rotating hole, a resistance coil is mounted in the sliding groove, and a fixing hole is formed in one end, away from the
brush head, of the connecting rod; and a telescopic motor is arranged on the inner wall of one end, close to the fixed disc, of the transmission rod, and the edge of one side, away from the telescopic motor, of a rotary disc is connected with the fixing hole througha rotary rod inserted into the fixing hole. Through the cooperative use of the devices, the
tongue fur cleaning effect of the electric
toothbrush can be improved, the use quantity of electronic components in the electric toothbrush is reduced, and the production cost can be reduced.