An engine that is lighter in weight includes a crankcase, a crankshaft, a body cylinder, a head cylinder, a piston, a piston ring and a cylinder fixing bolt. The piston ring is arranged on an outer peripheral surface of the piston. One end portion of the cylinder fixing bolt extends toward the head cylinder and an other end portion of the cylinder fixing bolt extends toward the crankcase. The cylinder fixing bolt connects the head cylinder, the body cylinder and the crankcase to one another. A lower section of the body cylinder is located within the crankcase. The piston ring abuts on the lower section when the piston is located at a bottom dead center.