Target values for position and orientation of a work point are provided in a robot program, dependent on which the program causes automatic movement of axles of the manipulator by a robot controller connected with the manipulator, to adjust a tool reference point of the manipulator. A robot base is movable via an auxiliary axle. Position values (provided by the robot program) of a planned position and orientation to be occupied by robot base for the tool reference point adjustment are automatically changed so the actual position of the robot base converges on a predetermined reference point, such as the work point or the tool reference point and the auxiliary axle is automatically moved to cause the robot base to occupy the position and orientation that correspond to the changed position values.