PURPOSE: To obtain a power generation device in which a motor car is made movable, in which a main shaft is turned via a beam so as to start a generator and which is of a simple structure by a method wherein the beam is attached to the main shaft and the motor car is installed at its tip.

CONSTITUTION: A plurality of motor cars 1 are installed, their roadway 11 is installed so as to be circular, a beam 2 is connected to the motor cars 1, one side of it is fixed to a main shaft 3, and an accelerator 4 is attached to the main shaft 3 so as to be connected to a generator 5. Then, the motor cars 2 are made movable at high speed, they are run on the circumference on the roadway 11, the main shaft 3 is rotated and accelerated by the accelerator 4, and the generator 5 is driven.