A laser apparatus that allows selection of a wavelength of output light from a plurality of options. The laser apparatus includes: a resonator made up from an output mirror and reflection means having a plurality of reflective surfaces fixed in position a laser medium disposed on an optical axis inside the resonator branch means branching an optical path of a light beam formed on the optical axis when light oscillates in the laser medium into a plurality of optical paths having an end at one reflective surface of the reflection means, the branch means forming a first optical path coinciding with the optical axis when located out of the optical axis, and forming a branch path by moving the light of the optical axis parallel when located on the optical axis.
