The laser beam branching apparatus incorporates a rotatable mirror holder (32) with a partially reflective mirror (33) for branching the beam (L) from the laser oscillator into beams (La, Lb), and a totally reflective mirror (34) for transfer of the branched beam (Lb) in a direction parallel to a beam (L). For beam branching the mirror holder is rotated from a position (B) into a position (A) in which the mirror (33) is in the path of the beam (L).
