To perform the solidification, hemostasis and incision of viable tissues and the grinding of bones and teeth by one device by obtaining the two kinds of the laser beams of different wavelengths from a laser beam source.

Fundamental laser beams oscillated and emitted by a solid laser excited by a semiconductor laser are made incident to an optical parametric oscillator and the two kinds of the laser beams of the different wavelengths are emitted. The two kinds of the laser beams are wave-guided to a laser cautery 54 by optical fibers 15 and 19 and a first laser beam ω01 provided with a wavelength range suitable for executing the solidification and the hemostasis to the viable tissues and a second laser beam ω02 provided with the wavelength range suitable for the incision of the viable tissues and the grinding of the bones and the teeth among them are utilized for operations. Thus, the two kinds of the operations are made possible by one device.