A laser apparatus includes a laser medium a light source that radiates light to the laser medium, thereby exciting the laser medium and raising the temperature thereof a reflecting unit having a first plane that reflects light within a predetermined wavelength range from light generated by excitation of the laser medium and an output mirror disposed opposite the reflecting unit, with the laser medium being interposed therebetween, and causing laser oscillation by inducing resonance of the light within a predetermined wavelength range between the first plane and the output mirror. The reflecting unit is configured to be movable between a position in which light resonance is induced between the output mirror and the first plane and the laser apparatus is set to an oscillation state and a position in which the laser apparatus is set to a non-oscillation state.
