PURPOSE: To eliminate the need for energy (fossil fuel, or the like)for power generation by providing a fluid pressure cylinder which is operated by the vertical motion of the vehicle body, a fluid pressure motor connected to the fluid outflow side of the cylinder, and a generator which derives power from the fluid pressure motor.

CONSTITUTION: A fluid-pressure (hydraulic/pneumatic) cylinder 1 is interposed between a vehicle body 2 and the lower arm 3a of the suspension. If the wheels are moved in B direction and the piston P of the cylinder 1 is moved in B direction during actual running, negative pressure is created in a head side chamber inside the cylinder 1, so a fluid is sucked into the head side chamber from a fluid storage tank 12 through a one-way valve B1. When the wheels return in A direction, the fluid in the head side chamber is pressurized by the piston P, and a fluid-pressure regulating tank 7 is pressurized through a one-way valve B2. The fluid pressure within the tank 7 is supplied to a fluid pressure motor 6 via a one-way pressure valve 14 to drive a generator 8.