To suppress the buckling deformation of a saw blade by cutting resistance and prevent cut bending of the thin saw blade in a highly precise cutting by the thin saw blade in a circular saw cutting machine.

This circular saw cutting machine has first and forth guide members 35 and 45 and second and fifth guide members 36 and 46 are arranged close in the front/rear of a cutting position of a material M to be cut in the saw blade side of the circular saw 28 fixed to the main spindle 27 and clamps the circular saw from the both sides with their approaching to the circular saw. The first and the forth guide members can be adjusted in their positions according to the shape of the material M to be cut. The guide members can suppress the buckling deformation of the saw blade by the cutting resistance in cutting the material to be cut according the size of the diameter of the material to be cut and effectively prevent the cut bending of the thin saw blade.