A light-emitting device manufacturing method comprises the steps of irradiating a substrate 2 having a III-V compound semiconductor layer 17 formed on a front face 2a with laser light L1 along lines to cut 5a, 5b, while locating a converging point P1 within the sapphire substrate 2 and using a rear face 2b thereof as a laser light entrance surface, and thereby forming modified regions 7a, 7b along the lines 5a, 5b within the substrate 2; then forming a light-reflecting layer on the rear face 2b of the substrate 2; and thereafter extending fractures generated from the modified regions 7a, 7b acting as a start point in the thickness direction of the substrate 2, and thereby cutting the substrate 2, the semiconductor layer 17 and the light-reflecting layer along the lines 5a, 5b, and manufacturing a light-emitting device.