DESCRIZIONE
An instruction value conversion section (31) of an operation target calculation section (30) converts an instruction signal from a joystick (25). In order to obtain a movement mode of a ship intended by an operator, a target propeller speed calculation section (32) calculates, using each converted value, target rotation speed of right and left propellers (13) and the propeller (14b) of a thruster (14). At a main engine operation control section (40), a slip rate determination section (41) calculates the slip rate U of a clutch mechanism (120) of a marine gear (12) in order to rotate the propellers (13) at the target rotation speed. A drive control section (42) controls operation of the main engine (11) and the clutch mechanism (120). Further, in a thruster operation control section (50), a drive control section (52) controls drive of the propeller (14b) in the rotational direction determined by an operation determining section (51).