To accurately irradiate a cutting position of a cutting blade with laser beams.

A laser oscillator 30 is supported in front of a holder 5, a brush 35 is provided on the cutting blade main body 8, and chips stuck to an irradiation part 30a of the laser oscillator 30 is swept out by the brush 35 in a process wherein the cutting blade main body 8 is moved from an upper limit position to a lower limit position.