A nitride semiconductor-based light emitting device is provided. The nitride semiconductor-based light emitting device is formed of a nitride semiconductor having a wurtzite lattice structure with the Ga face. The device has a substrate, a buffer layer, a first p-type contact layer, a second p-type contact layer, a first hole diffusion layer, a second hole diffusion layer, a light emitting active region, a second electron diffusion layer, a first electron diffusion layer, a second n-type contact layer and a first n-type contact layer, which are sequentially stacked. Such a structure may effectively employ quasi-two-dimensional free electron and free hole gases formed at heterojunction interfaces due to the spontaneous polarization and the piezoelectric polarization in the wurtzite lattice structure with the Ga face, and thus enhances the emission uniformity and emission efficiency of the light emitting device.