Abstract: A laser oscillator unit includes an amplification unit configured to amplify laser light and emit amplified laser light from an emitting portion; a case covering the amplification unit; and an outer support mechanism and an inner support mechanism provided on the case. The case is formed with a window portion. An outer movable leg allows the case to slide in a radial direction around an outer fixed leg. An inner movable leg allows the amplification unit to slide in the radial direction around an inner fixed leg. A straight line passing through a center of the outer fixed leg and a center of the inner fixed leg intersects with a straight line passing through the emitting portion and the window, and a laser optical axis emitted from the emitting portion and a laser optical axis emitted from the window portion coincide with each other.