A motorcycle including a supercharger-equipped combustion engine for a motorcycle, the combustion engine comprising: a crankshaft extending in a widthwise direction of the motorcycle; a supercharger configured to pressurize intake air; a clutch gear to be connected with a clutch and provided at one side of the crankshaft in the widthwise direction of the motorcycle, the clutch gear being formed on an outer periphery of an outermost side crank web; a supercharger gear configured to drive the supercharger, the supercharger gear being provided at the other side relative to the clutch gear and on a center side in the widthwise direction of the motorcycle relative to the clutch gear, wherein the supercharger gear is formed on a supercharger crank web disposed such that one or more journals are located between the clutch gear and the supercharger crank web; a first shaft body on which a driven-side supercharger gear configured to mesh with the supercharger gear is provided; a first rotator disposed on the first shaft body and at the one side relative to the driven-side supercharger gear in the widthwise direction of the motorcycle, the first rotator being configured to rotate with the driven-side supercharger gear to transmit power of the combustion engine to the supercharger; and characterised in that a cassette transmission holder is configured to support the first shaft body; wherein: the first rotator is disposed between the driven-side supercharger gear and the clutch gear in the widthwise direction of the motorcycle; and the cassette transmission holder is disposed at the inner side of the clutch in the widthwise direction of the motorcycle. a crankshaft extending in a widthwise direction of the motorcycle; a supercharger configured to pressurize intake air; a clutch gear to be connected with a clutch and provided at one side of the crankshaft in the widthwise direction of the motorcycle, the clutch gear being formed on an outer periphery of an outermost side crank web; a supercharger gear configured to drive the supercharger, the supercharger gear being provided at the other side relative to the clutch gear and on a center side in the widthwise direction of the motorcycle relative to the clutch gear, wherein the supercharger gear is formed on a supercharger crank web disposed such that one or more journals are located between the clutch gear and the supercharger crank web; a first shaft body on which a driven-side supercharger gear configured to mesh with the supercharger gear is provided; a first rotator disposed on the first shaft body and at the one side relative to the driven-side supercharger gear in the widthwise direction of the motorcycle, the first rotator being configured to rotate with the driven-side supercharger gear to transmit power of the combustion engine to the supercharger; and characterised in that a cassette transmission holder is configured to support the first shaft body; wherein: the first rotator is disposed between the driven-side supercharger gear and the clutch gear in the widthwise direction of the motorcycle; and the cassette transmission holder is disposed at the inner side of the clutch in the widthwise direction of the motorcycle. the first rotator is disposed between the driven-side supercharger gear and the clutch gear in the widthwise direction of the motorcycle; and the cassette transmission holder is disposed at the inner side of the clutch in the widthwise direction of the motorcycle.