A method for manufacturing a group III-V compound semiconductor represented by the general formula InxGayAlzN (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1) by metalorganic vapor phase epitaxy method is provided. The group III-V compound semiconductor has a semiconductor layer consisting of a p-type dopant-nondoped layer, and a semiconductor layer including a p-type dopant-doped layer. In the method, a reactor for growing the semiconductor layer consisting of a p-type dopant-nondoped layer and a reactor for doping a p-type dopant are mutually different.