A p-type semiconductor layer and an active layer and an n-type semiconductor layer are laminated in this order onto an n-type semiconductor layer. The n-type semiconductor layer is provided with an electron injection electrode on its upper part and a narrow current path is formed in its interior with the inversion diffusion layers. A positive hole injection electrode is provided on the p-type semiconductor layer. The direction of taking out the positive hole injection layer is the same as that of the electron injection electrode.