PURPOSE: To perform auxiliary machining by making use of the moving force of the work table of a finishing machine such as a machining center.

CONSTITUTION: The work table 2 of a machining center 1 is driven within the X-Y coordinates in accordance with the program control of a control means 9. When the work table 2 is driven, both an auxiliary fabricating arm 11 attached to the work table 2 and a gas fusion torch 12 as an auxiliary fabricating fixture supported by the aforesaid arm are moved together. A flat plate member W0 placed over a work setting section 14 provided in the outside of the machining center 1 is cut off by the flame of the gas fusion torch 12, so that a separate work W1 is thereby cut out.