A light-emitting device includes a package structure and a light-emitting chip. The package structure has a light exiting surface, a rear surface facing away from the light exiting surface, a groove inward recessed on the rear surface, and an outer surrounding side wall surrounding the groove. The light-emitting chip is disposed in the groove. The width of the package structure gradually decreases from the light exiting surface to the rear surface. The width of the groove gradually increases from inside to outside of the groove.