A light-emitting device comprises a photoluminescent layer that emits light including first light in an infrared region; and a light-transmissive layer located on the photoluminescent layer. At least one of the photoluminescent layer and the light-transmissive layer has a periodic structure having projections or recesses or both arranged perpendicular to the thickness direction of the photoluminescent layer. At least one of the photoluminescent layer and the light-transmissive layer has a light emitting surface perpendicular to the thickness direction of the photoluminescent layer, the first light being emitted from the light emitting surface. A refractive index nwav-a of the photoluminescent layer for the first light and a period pa of the periodic structure satisfy λa/nwav-a