REDUCTION/REVERSE GEAR

A reduction reverse gear (9) for marine vessel comprises a hydraulic clutch-type forward/reverse rotation switching mechanism (17) configured to convert rotation power of a main engine (7) mounted on a hull (2) to an output of forward rotation, neutral, or reverse rotation and to transfer the output to a propeller (5), a forward/reverse rotation switching valve (24) configured as a three-position switching type including a forward rotation position, a neutral position and a reverse rotation position and configured to control a switching operation of the forward/reverse rotation switching mechanism (17), and a trolling device (36) configured to regulate and control pressure of working oil flowing toward the forward/reverse rotation switching mechanism (17). The reduction reverse gear (9) is configured such that the reduction reverse gear (9) comprises an operation detection member (41) configured to detect an operation state of the forward/reverse rotation switching valve (24); and the trolling device (36) is configured to control the working oil so that the pressure of the working oil flowing toward the forward/reverse rotation switching mechanism (17) is not reduced regardless of detection information of the operation detection member (41) during normal propulsion.