A motorcycle including a supercharger-equipped combustion engine mounted thereon, the combustion engine comprising: a crankcase supporting an engine crankshaft; a cylinder block disposed above the crankcase; a supercharger having a rotation axis extending in a widthwise direction of the motorcycle and configured to pressurize intake air and supply it to the combustion engine; a drive gear configured to transmit power of the engine crankshaft to the supercharger; and a counter shaft rotatably supporting the drive gear, the counter shaft being disposed rearward of the engine crankshaft and extending parallel with the engine crankshaft; wherein the supercharger is disposed above the crankcase and rearward of the cylinder block and driven by the power of the engine crankshaft, the supercharger is disposed rearward of the counter shaft, and characterized in that a starter gear other than the drive gear is disposed on the counter shaft so as to be aligned together with the drive gear in the widthwise direction of the motorcycle, a starter motor driving the starter gear is disposed forwardly of the supercharger, an one-way clutch is provided between the drive gear and the starter gear so that the drive gear and the starter gear are connected with each other through the one-way clutch, whereby rotation of the starter gear is transmitted to the drive gear and rotation from the drive gear can be prevented from being transmitted to the starter gear, a speed gear (92, 94) is provided in the counter shaft and is configured to transmit power of the engine crankshaft to the supercharger, the speed gear (92, 94) being disposed outward of the drive gear and the starter gear being disposed inward of the drive gear in the widthwise direction of the motorcycle, the starter gear being disposed at a side opposite to the speed gear (92, 94) with respect to the drive gear in the widthwise direction of the motorcycle. a crankcase supporting an engine crankshaft; a cylinder block disposed above the crankcase; a supercharger having a rotation axis extending in a widthwise direction of the motorcycle and configured to pressurize intake air and supply it to the combustion engine; a drive gear configured to transmit power of the engine crankshaft to the supercharger; and a counter shaft rotatably supporting the drive gear, the counter shaft being disposed rearward of the engine crankshaft and extending parallel with the engine crankshaft; wherein the supercharger is disposed above the crankcase and rearward of the cylinder block and driven by the power of the engine crankshaft, the supercharger is disposed rearward of the counter shaft, and characterized in that a starter gear other than the drive gear is disposed on the counter shaft so as to be aligned together with the drive gear in the widthwise direction of the motorcycle, a starter motor driving the starter gear is disposed forwardly of the supercharger, an one-way clutch is provided between the drive gear and the starter gear so that the drive gear and the starter gear are connected with each other through the one-way clutch, whereby rotation of the starter gear is transmitted to the drive gear and rotation from the drive gear can be prevented from being transmitted to the starter gear, a speed gear (92, 94) is provided in the counter shaft and is configured to transmit power of the engine crankshaft to the supercharger, the speed gear (92, 94) being disposed outward of the drive gear and the starter gear being disposed inward of the drive gear in the widthwise direction of the motorcycle, the starter gear being disposed at a side opposite to the speed gear (92, 94) with respect to the drive gear in the widthwise direction of the motorcycle.