To increase the output light of a semiconductor laser element by arranging a pair of wave front conversion elements which converts the optical path of light beams emitted from ends of an optical semiconductor element into a package, and radiating the light beams outwards from a light transmission window.

Structure, where two light beams 2 are reflected in a pair of wave front conversion elements 3 and are reflected in the same direction at emitting of the light beams 2 from the end faces of an optical waveguide 4 as the end faces of an optical semiconductor element 1 formed of an end face light-emitting type optical semiconductor element, is installed in a package. Namely, the optical semiconductor element 1 is fixed to the flat recessed base 7 of the recessed part 6 of a supporting block 5, and the light beams 2 are emitted from the end faces so that they follow the recessed base 7 from the end faces. The wave front conversion elements 3 are inclined and arranged on the sides of the recessed part 6, at which the light beams 2 arrive. The beams 2 are made to be radiated outwards from the light transmission window. Thus, increase in the output light of the optical semiconductor element 1 can be realized.