An outboard motor equipped with a V-type engine is provided, in which an intake manifold and an auxiliary fuel tank are arranged rationally, thereby contributing to making the engine compartment compact. The outboard motor includes, in an engine compartment formed above a mount case, a V-type engine positioned so that heads of left and right cylinder banks face rearward. An intake manifold is disposed in a hollow between the left and right banks. An auxiliary fuel tank is disposed in an auxiliary equipment installation space that is formed between the left and right banks and the upper face of the mount case.