PURPOSE: To avoid getting an unmachineable state to cutting load in deburring, by installing a servomotor, a rotary tool body, a pulse oscillating device, etc., in a tool holding head of a machine, while installing a controller, a servoamplifier, etc., in the others.

CONSTITUTION: A bracket 1, a servomotor 2, a shaft 3 performing an axial stroke, a rotary tool body 4 and a pulse oscillating device 5 are all attached to a tool holding head of a machine M. Likewise,a pulse counter 6, a controller 7 independent from a controller Mc of the machine M, and a servoamplifier 8 controlling the servomotor 2 are installed in the others. And, the controller 7 detects size of machining load in comparison with the reference value, and outputs a floating control signal, which makes a rotary cutter 4a approach or keep away to or from a work W according to this machining load, to the servoamplifier 8. With this constitution, heavy and light cutting operations are repeated and smooth machining is performable.