A semiconductor device has at least a GaN system semiconductor having n-conductivity type and a GaN system semiconductor having p-conductivity type layered on a substrate. Electrodes are formed on both surfaces of the GaN system semiconductor layer having n-conductivity type and the GaN system semiconductor layer having p-conductivity type. A first electrode including at least silver and a second electrode excluding silver are formed on the surface of the GaN system semiconductor layer having p-conductivity type, with the second electrode surrounding the periphery of the first electrode. In addition, the first electrode has an opening at which the GaN system semiconductor layer having p-conductivity type is exposed inside of the outline of the first electrode. According to such structure, it is possible to realize a device having high luminous efficiency in use and high reliability.