PURPOSE: To accurately cut a workpiece in its cut position with no interference by giving a cut in amount against the workpiece by upper/lower right/left cutter guide frames, and serially giving a reciprocating motion to cutter blades by an operating ring.

CONSTITUTION: In an operating ring 64, its connection protruding part is reciprocation swiveled at an angle 2α with a center line C serving as the center through an operating crank mechanism, thus to reciprocate cutter holders 24a, 24b, 54a, 54b, arranged in guide grooves 23a, 23b, 53a, 53b of upper/lower right/ left cutter guide frames 21, 22, 51, 52 correlated to engaging groove parts 67a, 67b, 67c, 67d of the operating ring 64, along the guide grooves 23a, 23b, 53a, 53b. In this condition, drive motors 16, 46 of upper/lower operating mechanisms 10 and right/left operating mechanisms are synchronously actuated and rotated by a predetermined amount, so that each cutter blade 33 is moved respectively in X, Y-axis directions by each cutter guide frame 21, 22, 51, 52 and successively given a cut in amount.