The light-concentration density or laser power of a combined laser beam bundle, obtained by combining individual laser beams that are caused to oscillate by and are output from a plurality of single-emitter LDs, is increased efficiently, with high quality. On a bottom plate or a unit base 22 of the laser unit 10, there are disposed: a pair of stacked laser beam creation units 24L, 24R which are arranged with left-right symmetry with respect to a center line N; a single wavelength stabilizing element (VBG) 26 of which an incidence plane vertically intersects the center line N; a pair of primary anamorphic prisms 28L, 28R which are arranged separately on the right and left of the center line N; a mirror-type beam rotation element 30 disposed on the center line N; and a secondary anamorphic prism 32 disposed offset from the beam rotation element 30 in a direction (X-direction) perpendicular to the center line N.