To solve such a problem that in the case where the size of the whole engine including a supercharger 10 or the like is large, the possibility of mounting the engine to a vehicle is decreased and particularly, in the vehicle in which the height of its engine hood is limited to be low, the mounting is impossible.

A cooler housing 14 is arranged in between an engine body and a supercharger 10 disposed thereabove in the vertical direction of the engine. A pair of intercoolers 12 (12R and 12L) are arranged inside the cooler housing 14 in parallel in the widthwise direction of the engine and, further, an intake air inlet and its outlet are installed at one side of each intercooler 12 in the engine widthwise direction and at the other side thereof, respectively. An air intake device is thereby constituted such that the intake air flows in the intercoolers 12 along the engine widthwise direction.