To provide a gravity rotary device that rotates by utilizing gravity acting on weights and to provide a power generator having the same.

The gravity rotary device includes two discs B provided with holes A of an approximately elliptic cylinder shape at 16 positions and 16 weights C of an approximately circular cylinder shape. The approximate ellipse is composed of a combination of two arcs of a same radius. Holes A are arranged in a concentric shape of a disc B. An angle between a straight line that connects a center of a disc B and a center of a hole A and a straight line that connects both ends of a hole A is 45 degrees. A weight C is inserted in each of holes A and sandwiched by the discs B. By gravity acting on the weights C, clockwise moment around an axis of a straight line passing through the centers of the discs B occurs and clockwise rotation is generated.