A semiconductor light emitting device of the present invention includes a substrate (1), an n-GaN layer (2) supported by the substrate (1), a p-GaN layer (7) which is located farther from the substrate (1) than the n-GaN layer (2) is, an active layer (4) formed between the n-GaN layer (2) and the p-GaN layer (7) and containing InGaN, a sublimation preventing layer (5) formed between the active layer (4) and the p-GaN layer (7) and containing InGaN, and an In composition gradient layer (6) sandwiched between the sublimation preventing layer (5) and the p-GaN layer (7) and having such In composition ratio gradient that the In composition ratio decreases in the thickness direction toward the p-GaN layer (7).