To provide a device which stores air in an air compressor by obtaining the right and left reciprocating motion by utilization of repulsion and attraction of a permanent magnet for movement of an air cylinder piston.

A permanent magnet N-pole 1 is grounded to the upper surface of a permanent magnet N-pole 5. The permanent magnet S-pole 5 is mounted with the permanent magnet so that the permanent magnet N-pole on the upper face smoothly rolls. When a grounding metal fitting 19 of a lever type on/off switch on the upper surface of the permanent magnet N-pole comes into contact with the lever type on/off switch 2, the permanent magnet N-pole 3 is turned on and serves an N-pole, and the permanent magnet N-pole 1 moves in the direction of extension of the air cylinder piston rod 15 by the repulsion between the N-pole and the S-pole. An air valve 18 is provided which sends the air to the air compressor 9 through air hoses 13, 14 by movement of the air cylinder piston rod 15 and acts as one way valve so that the air does not flow in the reverse direction.