To improve the sealing performance of an exhaust pipe extending from one side to the other side of a member at the side of an engine.

This exhaust device for the outboard engine includes the exhaust pipe 13 to form a catalyst exhaust passage extending from one side to the other side of a guide exhaust 2. The exhaust pipe 13 has an expansion portion 112 in an area extending in the cross direction of the outboard engine. The expansion portion 112 is so formed that a pipe member (an inner cylinder 82) located at the other side is movable in cross direction relative to a pipe member (an outer cylinder 82) located at one side.