A process for producing a nitride semiconductor according to the present invention includes: step (A) of provided an n-GaN substrate 101; step (B) of forming on the substrate 101 a plurality of stripe ridges having upper faces which are parallel to a principal face of the substrate 101; step (C) of selectively growing AlxGayInzN crystals (0≦x, y, z≦1: x+y+z=1) 104 on the upper faces of the plurality of stripe ridges, the AlxGayInzN crystals containing an n-type impurity at a first concentration; and step (D) of growing an Alx′Gay′Inz′N crystal (0≦x′, y′, z′≦1: x′+y′+z′=1) 106 on the AlxGayInzN crystals 104, the Alx′Gay′Inz′N crystal 106 containing an n-type impurity at a second concentration which is lower than the first concentration, and linking every two adjoining AlxGayInzN crystals 104 with the Alx′Gay′Inz′N crystal 106 to form one nitride semiconductor layer 120.