A method of growing a gallium nitride crystal, includes: a step of partially forming, on a ground substrate (U), a mask (M) inhibiting epitaxial growth of a gallium nitride crystal; and a step of epitaxially growing, while doping carbon, the gallium nitride crystal on the ground substrate (U) in which the mask (M) is formed. In the epitaxial growth, a first crystal region is grown from a periphery of the mask (M) toward inside. C-axis direction is reversed in the first crystal region relative to a second crystal region grown on a region where the mask (M) is not formed in the ground substrate (U). Therefore, a stable crystal grain boundary is produced at the boundary between the first and second regions, and a density of dislocations in the crystal is efficiently reduced.