The present invention provides a nitride semiconductor device. The nitride semiconductor device comprises an n-type nitride semiconductor layer formed on a nitride crystal growth substrate. An active layer is formed on the n-type nitride semiconductor layer. A first p-type nitride semiconductor layer is formed on the active layer. A micro-structured current diffusion pattern is formed on the first p-type nitride semiconductor layer. The current diffusion pattern is made of an insulation material. A second p-type nitride semiconductor layer is formed on the first p-type nitride semiconductor layer having the current diffusion pattern formed thereon.