A two-dimensional photonic-crystal laser (10; 20; 30) comprising: a) a substrate made of an n-type semiconductor; b) a p-type semiconductor layer provided on an upper side of the substrate and made of a p-type semiconductor; c) an active layer provided on an upper side of the p-type semiconductor layer; d) a two-dimensional photonic-crystal layer (16; 16A; 16B) provided on an upper side of the active layer and including a plate-shaped base body (161; 161A; 161B) made of an n-type semiconductor in which modified refractive index areas whose refractive index differs from the base body (161; 161A; 161B) are periodically arranged; e) a first tunnel layer provided between the substrate and the p-type semiconductor layer and made of an n-type semiconductor having a carrier density higher than a carrier density of the substrate; f) a second tunnel layer provided in contact with the first tunnel layer between the first tunnel layer and the p-type semiconductor layer, and made of a p-type semiconductor having a carrier density higher than a carrier density of the p-type semiconductor layer; g) a first electrode (181; 281; 381) provided on a lower side of the substrate or in the substrate; h) a second electrode (182; 282) provided on an upper side of the two-dimensional photonic-crystal layer (16; 16A; 16B); and i) a groove provided from a surface on an upper side of the two-dimensional photonic-crystal laser (10; 20; 30), having a bottom face at a position between an upper face and a lower face of the substrate, and having a frame-like shape in a cross section parallel to the two-dimensional photonic-crystal layer (16, 16A, 16B), wherein the first electrode (181 281; 381) is provided on the bottom face of the groove. a) a substrate made of an n-type semiconductor; b) a p-type semiconductor layer provided on an upper side of the substrate and made of a p-type semiconductor; c) an active layer provided on an upper side of the p-type semiconductor layer; d) a two-dimensional photonic-crystal layer (16; 16A; 16B) provided on an upper side of the active layer and including a plate-shaped base body (161; 161A; 161B) made of an n-type semiconductor in which modified refractive index areas whose refractive index differs from the base body (161; 161A; 161B) are periodically arranged; e) a first tunnel layer provided between the substrate and the p-type semiconductor layer and made of an n-type semiconductor having a carrier density higher than a carrier density of the substrate; f) a second tunnel layer provided in contact with the first tunnel layer between the first tunnel layer and the p-type semiconductor layer, and made of a p-type semiconductor having a carrier density higher than a carrier density of the p-type semiconductor layer; g) a first electrode (181; 281; 381) provided on a lower side of the substrate or in the substrate; h) a second electrode (182; 282) provided on an upper side of the two-dimensional photonic-crystal layer (16; 16A; 16B); and i) a groove provided from a surface on an upper side of the two-dimensional photonic-crystal laser (10; 20; 30), having a bottom face at a position between an upper face and a lower face of the substrate, and having a frame-like shape in a cross section parallel to the two-dimensional photonic-crystal layer (16, 16A, 16B),