The invention discloses a driving device for an electric
toothbrush, which comprises a
driving circuit, an external shell, a revolving shaft, a bearing, a coil fixing bracket, a boot shape pole
yolk, a driving coil, a
magnet positioning post, a permanent
magnet, an end cover and a damping device which is used for assisting the revolving shaft to do reciprocating movement; a common rotor and a common
stator are adopted to control the current direction of the coil in the rotor in a matching manner so as to change the direction of the
magnetic field and cause the rotor to rotate with
high frequency in a reciprocating way; the alternating
magnetic field in the
stator is generated by adopting alternating rectangular wave current; the setting of the
driving circuit is simpler and is beneficial to control; the coil fixing bracket is formed by the
abutment joint of two semi-circular iron cores, which causes the winding process of the coil to become simpler; in addition, the fixing bracket is formed by overlying of multiple lays of magnetic conducting elements, which ensures that the
magneto resistance and the
eddy current of a middle
magnetic loop are relatively decreased, reduces the lossof the
magnetic field, improves the efficiency and has simple structure; the revolving shaft is also provided with the damping device for assisting the movement of the alternating magnetic field, thus causing the reciprocating movement of the revolving shaft to be smoother and greatly improving the
system efficiency.