A method of growing a semi-polar nitride single crystal thin film. The method includes forming a semi-polar nitride single crystal base layer on an m-plane hexagonal system single crystal substrate, forming a dielectric pattern layer on the semi-polar nitride single crystal base layer, and growing the semi-polar nitride single crystal thin film on the semi-polar nitride single crystal base layer having the dielectric pattern layer in a lateral direction. The growing of the semi-polar nitride single crystal thin film in a lateral direction includes primarily growing the semi-polar nitride single crystal thin film in the lateral direction such that part of a growth plane on the semi-polar nitride single crystal base layer has an a-plane, and secondarily growing the semi-polar nitride single crystal thin film in the lateral direction such that sidewalls of the primarily grown semi-polar nitride single crystal thin film are combined to have a (11 22) plane.