An engine including a supercharger driven by a power of the engine to pressurize an intake air for the engine, wherein the supercharger comprises: a rotary shaft body provided with a supercharge rotating body for pressurizing the intake air; a transmission rotating body which is provided in the rotary shaft body for transmitting the power to the rotary shaft body; and a supercharger casing to accommodate therein the rotary shaft body and the transmission rotating body, the supercharger casing rotatably supporting the rotary shaft body and the transmission rotating body; characterized in that: the supercharger casing is detachably fixed to an upper surface of a crankcase of the engine, a transmission covering is removably fitted to the crankcase, removal of the transmission covering allowing a transmission to be removed, the supercharger casing is formed with an access opening that enables access from an axial direction of the rotary shaft body to the transmission rotating body, the access opening is formed in the supercharger casing and is formed at opposite side of the supercharge rotating body relative to the transmission rotating body, the power is transmitted to the transmission rotating body through an endless stripe-shaped transmitting member, and the endless stripe-shaped transmitting member is trained around a first sprocket on an engine side and a second sprocket forming the transmission rotating body. removal of the transmission covering allowing the first sprocket to be removed, and the access opening is closed by a cap removable relative to the supercharger casing. a rotary shaft body provided with a supercharge rotating body for pressurizing the intake air; a transmission rotating body which is provided in the rotary shaft body for transmitting the power to the rotary shaft body; and a supercharger casing to accommodate therein the rotary shaft body and the transmission rotating body, the supercharger casing rotatably supporting the rotary shaft body and the transmission rotating body; characterized in that: the supercharger casing is detachably fixed to an upper surface of a crankcase of the engine, a transmission covering is removably fitted to the crankcase, removal of the transmission covering allowing a transmission to be removed, the supercharger casing is formed with an access opening that enables access from an axial direction of the rotary shaft body to the transmission rotating body, the access opening is formed in the supercharger casing and is formed at opposite side of the supercharge rotating body relative to the transmission rotating body, the power is transmitted to the transmission rotating body through an endless stripe-shaped transmitting member, and the endless stripe-shaped transmitting member is trained around a first sprocket on an engine side and a second sprocket forming the transmission rotating body. removal of the transmission covering allowing the first sprocket to be removed, and the access opening is closed by a cap removable relative to the supercharger casing. the supercharger casing is detachably fixed to an upper surface of a crankcase of the engine, a transmission covering is removably fitted to the crankcase, removal of the transmission covering allowing a transmission to be removed, the supercharger casing is formed with an access opening that enables access from an axial direction of the rotary shaft body to the transmission rotating body, the access opening is formed in the supercharger casing and is formed at opposite side of the supercharge rotating body relative to the transmission rotating body, the power is transmitted to the transmission rotating body through an endless stripe-shaped transmitting member, and the endless stripe-shaped transmitting member is trained around a first sprocket on an engine side and a second sprocket forming the transmission rotating body. removal of the transmission covering allowing the first sprocket to be removed, and