Abstract: A positive-displacement fluid motor wherein a rotating member rotated by pressurized fluid flows to and from fluid chambers can be stopped at a desired one of at least one predetermined angular position by a torque produced by the motor itself. The fluid is supplied into at least one advancing fluid chamber of the fluid chambers which acts to rotate the rotating member in an operating direction of the motor, while causing the fluid to be discharged from at least one reversing fluid chamber of the fluid chambers which acts to rotate the rotating member in a direction opposite to the operating direction, if a motor stop command is generated when the desired angular position is ahead of a current position of the rotating member in the operating direction of the motor.