A permanent magnet motion conversion device includes spaced stationary permanent magnets and a carriage having permanent magnets located adjacent the ends of the carriage. The carriage shuttles back and forth between the permanent magnets as a result of magnetic repulsion when shield plates are moved into and out of shielding positions in front of the stationary magnets. The carriage is provided with a connecting rod which is connected to a crank shaft. More than one carriage can be employed.