To provide an electric motor which can be rotated continuously for a long time, with a small amount of energy.

The electric motor that includes a rotor provided with a magnet and a stator provided with a magnetic circuit which can be opened and closed, or an electric motor that includes a rotor provided with a magnetic circuit which can be opened and closed and a stator provided with the magnet, is constituted in such a manner that the magnetic circuit is made to open and close in a state interlocked with the rotation of the rotor. When the magnet of the rotor or the stator is placed adjacent to the magnetic circuit, the magnet of the rotor or the stator and a magnetic pole of the magnet of the magnetic circuit are arranged so as to be opposed.