To convert a reciprocating (vertical) operation into a rotary operation by turning on/off the switch of one electromagnet and attracting/repulsing the magnet with both poles of the electromagnet.

A magnet 2 is fitted to a reciprocating part 3 (part equivalent to the position of an internal combustion engine). Then, an electromagnet 1 is fixed to a main body 22 so that it attracts/repulses the magnet 2. The reciprocating part 3 is supported by supporting parts 6, 7, 8 and 9 and the reciprocating operation of the reciprocating part 3 is converted into a rotary operation with a connection bar 4 and a crank 5. Force generating the reciprocating operation in the electromagnet 2 is the attractive force of the iron core of the electromagnet 1 and the magnet 2 when the switch of the electromagnet 1 is turned off and the repulsive force of the iron core of the electromagnet 1 and the magnet 2 when the switch of the electromagnet 1 is turned on. When electric energy is inputted to one electromagnet 1 in such a case, the two magnets 2 are simultaneously attracted/repulsed each other at the two places of both poles in the electromagnet 1 and the reciprocating operation is executed. The reciprocating operation in the two places is converted into the rotary operation.