To obtain an electric machine which can control the quantity of a magnetic flux in proportion to torque generated by a current.

In the electric machine which has a stator where winding is stored in a slot, a tip 6 of each tooth 5 being the sidewall of the slot is made to be able to rotate around the rotation center 11. The tip 6 rotates around the rotation center 11, according to the torque generated by an applied current, so as to vary the length of an air gap to a rotor or a moving member. Hereby, the quantity of magnetic flux can be varied, and the operation range can be widened in a variable-velocity motor.