PURPOSE: To determine working information while inputting working position information by storing position information and form information of a tool and comparing them with position information and form information of a working object.

CONSTITUTION: A cutting tool and the working object are displayed on a display picture, and position information of the tool is changed by input information from a position input means 11 and is stored in a tool position and form storage means 12 and is compared with position information of the working object stored in a working object position and form storage means 13; and when it is discriminated by a contact discriminating means 14 that the tool and the working object are brought into contact with each other, the working start state is set. When the tool is moved into the working object, position information of the tool and that of the working object are synthesized by a position synthesizing means 15, and form information of the working object is changed by a working object deforming means 16, and working of the object is advanced, and the working is terminated when the tool and the working object are separated from each other.