In an apparatus for controlling operation of an outboard motor having a shift shaft to be rotated in response to manipulation by an operator to switch a shift position between an in-gear position that enables driving force of a prime mover to be transmitted to a propeller by engaging a clutch with one of a forward gear and a reverse gear, and a neutral position that cuts off transmission of the driving force by disengaging the clutch from the forward or reverse gear, comprising a neutral operation detector connected to the shift shaft and adapted to detect a neutral operation in which the shift position is switched from the in-gear position to the neutral position; and a driving force controller adapted to conduct driving force decreasing control to decrease the driving force of the prime mover when the neutral operation is detected.