To provide a circular saw cutter which can omit a milling process for the cut surfaces by accurately cutting off piled workpieces, and can replace four or five fret cutter with one circular saw cutter.

The circular saw cutter comprises a bed 1; a head moving means for reciprocating a head in the X-axis direction perpendicular to the direction for supplying a workpiece by providing guide rails 1e, 1f on the bed 1; the head 5 which is mounted on the guide rails 1e, 1f, and rotatably supports a main spindle 3 in the Z-axis direction that is the same direction as the axial direction of the main spindle 3 having the circular saw 3 mounted thereon to cut off the workpiece W, and mounts a motor 4 thereon to rotate the circular saw 3; a workpiece supply device 30 arranged on the left side below the bed 5 to supply the workpiece W to the cutting-off position; a head speed control means for controlling the moving speed of the head 5; a workpiece speed control means for servo-controlling the workpiece W on the workpiece supply device 30; and a workpiece clamping device 20 for clamping the workpiece W supplied from the workpiece supply device 30 at the cutting-off position.