To provide a propelling machine for small-sized ship, capable of changing over a shifting mechanism from a forward to a neutral position with a small force and preventing the engine from stalling as much as possible, even at abrupt shifting to the reverse position.

A propeller 4 is driven by an engine 2 via a shifting mechanism 11, and a throttle valve 54 is installed on a intake pipe 52 to lead the air into each cylinder 7 of the engine. A bypass passage 55 is formed to bypass the throttle valve, and an ISC valve 81 is installed in the bypass passage. When the throttle valve in the largely opened condition is closed abruptly, a control device 91 makes control, so that the ISC valve is closed slowly, when the ship speed is high and is closed quickly when the ship speed is low.