PURPOSE: To convert the compliance easily by storing an imaginary compliance coefficient as an instruction data, and providing an input key to input the above coefficient to a teach box, in a device to compliance-control a robot.

CONSTITUTION: An instruction device 40 attached to a robot control device 20 is added to a robot object position, so as to make the system to set an imaginary compliance, and when the mode converting switch of the instruction device 40 is operated to convert, the mode of a jog operation key is converted in the order, a top object position, an imaginary inertia constant, an imaginary damping coefficient, an imaginary spring coefficient, the top object position..., and the values are set. The set object position and the set imaginary compliance coefficient are stored separately in an object value memory 212, the object position is stored in the value of the position components in the X to Z directions; and the posture component of the roll angle, the pitch angle, and the yaw angle; while the imaginary compliance coefficient is stored by collecting the imaginary inertia coefficient, the imaginary damping coefficient, and the imaginary spring coefficient.