The present invention is directed to enable the shape of a bump stopper to be easily changed in accordance with a change in specifications, the bump stopper for performing position regulation so that, when an engine generator shakes, the generator body does not come off from an external frame. A position regulating apparatus has a generator body (4) made of an engine (2) and a generator (3) driven by the engine, and a frame (7) surrounding the periphery of the generator body (4). The frame (7) is provided with a bump stopper (40) as a rod member. The bump stopper (40) is attached to a housing (70) of the engine (2) and disposed horizontally. The bump stopper (40) regulates the position in the horizontal direction of the generator body (4) within a preset range. Receiving plates (60) disposed so as to face both end faces of the stopper body (41) are provided. The round bar as the body (41) of the bump stopper (40) has a crank shape which reduces an impact by generating bending moment.