To provide an electric power generator using movement of a person or a vehicle in which the power generator is installed under a sidewalk or a roadway to using change in weight caused by traffic of the person or the vehicle.

The power generator using the change in weight caused by the traffic is installed under the sidewalk or the roadway. A structure includes serrated shaft 2 fixed on a tread board 1, a gear 4 meshing with a serration of the shaft 2, and a shaft 5 of the gear 4 connected to a flywheel 7 and the power generator 8 through a ratchet mechanism 6. Accordingly when the person steps on the tread board, the power generator is driven, and when the person passes away, the tread board is returned by a spring. Every time the person passes, this motion is repeated to generate power. In case of passage of the vehicle, the power is generated in the same manner. One or more of a power generating mechanism like this is/are lined under the sidewalk or the roadway and an iron or rubber sheet may be placed over it to level a road surface for the person or the vehicle to easily pass over. The power generator is connected to a battery through a rectifier and a regulator to store electricity. The electricity stored in this way can be used as a power source for an illumination lamp or other electric appliances.