A face-up optical semiconductor device can be prepared by forming an n-type GaN layer, an active layer, and a p-type GaN layer on a C-plane sapphire substrate. Parts of the p-type GaN layer and the active layer can be removed, and a transparent electrode can be formed over all or most of the remaining p-type GaN layer. A p-side electrode including a pad portion and auxiliary electrode portions can be formed on the transparent electrode layer. An n-side electrode can be formed on the exposed n-type GaN layer. On regions of the transparent electrode layer where weak light emission regions may be formed, outside independent electrodes can be provided. They can be disposed on concentric circles with the n-side electrode as a center or tangent lines thereof so as to be along the circles or the tangent lines. The outside independent electrodes can diffuse current from the p-side electrode to the n-side electrode flowing through the transparent electrode layer into the short side end portions of the transparent electrode layer, thereby decreasing the weak light emission regions.