An MQW-structure light-emitting layer is formed by alternately stacking InGaN well layers and AlGaN barrier layers. Each well layer and each barrier layer are formed so as to satisfy the following relations: 12.9≦−2.8x+100y≦37 and 0.65≦y≦0.86, or to satisfy the following relations: 162.9≦7.1x+10z≦216.1 and 3.1≦z≦9.2, here x represents the Al compositional ratio (mol %) of the barrier layer, and y represents the difference in bandgap energy (eV) between the barrier layer and the well layer, and z represents the In compositional ratio (mol %) of the well layer.