To provide a laser beam machine equipped with a bend mirror vibration proof mechanism for the purpose of protecting a bend mirror from vibration due to expanding/contracting motion during the motion of bellows.

In the laser beam machine, a laser beam Le emitted from a laser generator is guided to the machining head through bends such as a second and first bend mirrors 1, 1'. The machinen is provided with the bend mirror vibration proof mechanism, in which the bend mirror 1 fixed on a support 3 forming a mirror bracket is surrounded with a box 2 having opening in the incident and reflecting directions that are the X axis and Y axis optical paths, an X axis optical path bellows 4 and a Y axis optical path bellows 5 that protect the optical path of the laser beam Le are connected in the two X and Y axis directions on the open side in the incident and reflecting directions of the box 2, thereby making the optical path a hermetically sealed structure then the box 2 is mounted on the mirror bracket 3 through a vibration proof member 7, so that vibration from the optical axis bellows to the bend mirror 1 is dampened and absorbed.