To carry out two kinds of works, that is, cutting-off and polishing of a workpiece at the same time by means of a single machine.

In order to solve the problem described above, a circular saw cutter 1 comprises: a spindle 47 which rotates by being connected to the output portion 15a of a power transmitting portion 15 and serves as a holding means 13 for rotatably holding a circular saw blade 11; and the outer flange portion 49 and the inner flange portion 51 which are attached to the end portion of the spindle 47 and hold the circular saw blade 11. A discoidal polishing body 73 is dismountably attached to the front surface of the outer flange portion 49. A dust preventing hood 87 is attached to a safety cover 85 for covering the circular saw blade 11 so as to prevent the scattering of polishing dust.