A V-type multi-cylinder 4-cycle engine E accommodated in an engine room in an outboard motor includes a pair of left and right banks. A surge tank is disposed in a space defined between both the banks and connected to two left and right combustion chambers through intake ports. A throttle body is connected to a lower portion of the surge tank and also to an intake silencer mounted in a left space of the engine room through an elbow. A subsidiary tank for supplying a fuel to an injector is disposed symmetrically with the intake silencer in a right space of the engine room. The employment of the above-described layout makes it possible to make an intake device move compact in the 4-cycle engine.