To provide a power unit structure, not discharging a substance harmful to human body.

A permanent magnet (2) and a permanent magnet support (3) are disposed inside a columnar cylinder, the permanent magnet support (3) and a crankshaft (5) are connected to each other by a connecting rod (4), some of power is transmitted to a shaft (7) and a magnet rotor (8) by gears (6a), (6b) fitted to the crankshaft (5), and repulsive magnetic force and attractive magnetic force are applied to the permanent magnet (2) by permanent magnets (9), (10) of the magnet rotor (8), thereby driving a unit to obtain rotating power of the crankshaft (5).