PROBLEM TO BE SOLVED: To provide a laser device with simple configuration having a wavelength selection mechanism in which a risk of causing wavelength deviation or optical path angle deviation is low.SOLUTION: A laser device selecting wavelength of light outputted from a plurality of wavelengths comprises: a resonator formed of an output mirror and reflection means having a plurality of fixed reflection surfaces and a laser medium arranged on an optical axis in the resonator branch means for branching an optical path on the optical axis, formed by oscillation of light from the laser medium, into a plurality of optical paths having any reflective surface as an end, forming a first optical path identical to the optical axis when it is off-axis, and forming a branch optical path by moving the light in parallel on the optical axis when it is on-axis and moving means for moving the branch means on-axis and off-axis. Wavelength of light outputted is determined depending on the reflective surface.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2018,JPO&INPIT
