PURPOSE: To fairly remove a bur, by controlling the movement of a rotating cutting tool based on the acceleration of the rotating cutting tool.

CONSTITUTION: Control means 20, 21 use an impedance control equation virtually expressing a reaction force by an inertia term, a viscous term and stiffness term, finding the acceleration of a rotating cutting tool 16 for a soft molding 1, based on the detection value of a force sensor 17, and controlling a moving mechanism 19 so that the rotating cutting tool 16 is moved at the acceleration thereof. Namely a moving speed X' is found from the timely change of the present position X of the rotating cutting tool 16, and also the acceleration X" of the rotating cutting tool 16 is found from a reaction force (f) by the force sensor 17 a target reaction force fr, target position Xr and various coefficients M, K, B. The moving speed X' of the rotating cutting tool 16 is operated with the acceleration X" of the rotating cutting tool 16 being integrated by time, and the command for making the moving speed X' is output to the moving mechanism 19. The bur can thus be fairly removed.