To provide a workpiece supplying device for a circular saw cutter, capable of eliminating milling at a cut place of flat steel workpiece by precise cutting dimensions, and replacing 4 or 5 fret saw cutters with one cutter, and to provide a workpiece fixing method therefor.

The workpiece supplying device 30 for the circular saw cutter 10 comprises a roller conveyer 32a, a base 31a standing straight, a saddle 34 in which a ball screw 33a is screwed, guide rails 35, 35 vertically provided on a front surface 34a of the saddle 34, a base 36 placed on the guide rails 35, 35 and moving in a vertical direction, a clamper 36a fixed on the base 36 and holding a fixing claw 36c gripping a lower surface of workpiece W, a clamper claw 36b supported by the clamper 36a and gripping an upper surface of the workpiece W, and a cylinder 37 moving the clamper claw 36b in a thickness (up-and-down) direction of the workpiece W.