A gallium nitride vapor phase epitaxy apparatus capable of doping magnesium is provided. The apparatus is used in vapor phase epitaxy not using organic metal as a gallium raw material. The apparatus comprises a reactor vessel and a wafer holder. The apparatus comprises a first raw material gas supply pipe configured to supply a first raw material gas containing gallium. The apparatus comprises a second raw material gas supply pipe configured to supply a second raw material gas, which contains nitrogen and configured to react with the first raw material gas. The apparatus comprises a third raw material gas supply pipe configured to supply a third raw material gas containing magnesium. The third raw material gas supply pipe is configured capable of placing a magnesium-based oxide on its supply path. The apparatus comprises a first heating unit configured to heat the magnesium-based oxide in a first temperature range.