A shift-in operation determination device determines a shift-in operation based on a signal in accordance with an operation of a remote control lever. An ignition timing operation device retards an ignition timing of an engine based on a determination result of the shift-in operation by the shift-in operation determination device. A shift-in command device engages a shift actuator and a dog clutch with either of a forward traveling bevel gear or a rearward traveling bevel gear in a state where the ignition timing of the engine is retarded. The shift-in operation determination device works to prevent a shock which occurs at a shift-in while maintaining a stable engine output in an outboard motor.