PURPOSE: To shorten the machining lead time without increasing the revolving speed and feeding speed of a tool, prevent the enlargement of a device, reduce the machining cost, simplify the control of a manipulator, and reduce the facility cost.

CONSTITUTION: The drive and positions of prescribed tools (grinding wheels) 30, 31 provided on a manipulator (robot) 10 and the relative attitudes of the tools against a work (die) 50 can be controlled, and the work 50 can be fed for machining in this machining device. Multiple tools 30, 31 are provided on the manipulator 10 so that their drive, positions, and relative attitudes against the work 50 can be independently controlled. The interference avoidance distance for avoiding the mutual interference during the respective machining work is set between the tools 30, 31.