A scooter-type motorcycle has a structure in which an article accommodation box is disposed below a rider's seat which is upward openable, and a power unit including an engine and a power transmission is disposed below the article accommodation box to be vertically swingable together with a rear wheel. The power unit is connected to a swing shaft which is disposed above a front portion of an engine crank case, and a starter motor for starting an operation of the engine is disposed above a rear portion of the crank case. An air cleaner, a suction pipe, a throttle body and an intake manifold are arranged substantially horizontally from a rear side portion of a motorcycle body towards a front side portion thereof so as to constitute an engine intake device to be connected to the engine. The throttle body is disposed between the swing shaft and the starter motor.