A light emitting device (2000, 3000), comprising: a substrate including: a base member including a front surface extending in a first direction as a longer direction and a second direction as a shorter direction, a rear sur-face located opposite to the front surface, a bottom surface adjacent to and perpendicular to the front surface, and a top surface located opposite to the bottom surface, and a first wiring portion located on the front surface, and a second wiring portion located on the rear surface; a plurality of light emitting elements (20A, 20B, 20C) including a first light emitting element electrically connected with the first wiring portion and placed on the first wiring portion; a first reflective member covering lateral surfaces of the plurality of light emitting elements (20A, 20B, 20C) and the front surface of the base member; and a light-transmissive member disposed over the plurality of light emitting elements (20A, 20B, 20C); wherein: the base member has a plurality of recessed portions each opened on the rear surface and the bottom surface, the plurality of recessed portions including a first recessed portion; the substrate includes a third wiring portion covering an inner wall of the first recessed portion, and a via which runs through the base member from the front surface to the rear surface; and the via electrically connects the first wiring portion, the second wiring portion and the third wiring portion to each other, wherein the via is in direct contact with the first wiring portion, the second wiring portion and the third wiring portion. a base member including a front surface extending in a first direction as a longer direction and a second direction as a shorter direction, a rear sur-face located opposite to the front surface, a bottom surface adjacent to and perpendicular to the front surface, and a top surface located opposite to the bottom surface, and a first wiring portion located on the front surface, and a second wiring portion located on the rear surface; a plurality of light emitting elements (20A, 20B, 20C) including a first light emitting element electrically connected with the first wiring portion and placed on the first wiring portion; a first reflective member covering lateral surfaces of the plurality of light emitting elements (20A, 20B, 20C) and the front surface of the base member; and a light-transmissive member disposed over the plurality of light emitting elements (20A, 20B, 20C); wherein: the base member has a plurality of recessed portions each opened on the rear surface and the bottom surface, the plurality of recessed portions including a first recessed portion; the substrate includes a third wiring portion covering an inner wall of the first recessed portion, and a via which runs through the base member from the front surface to the rear surface; and the via electrically connects the first wiring portion, the second wiring portion and the third wiring portion to each other, wherein the via is in direct contact with the first wiring portion, the second wiring portion and the third wiring portion. the base member has a plurality of recessed portions each opened on the rear surface and the bottom surface, the plurality of recessed portions including a first recessed portion; the substrate includes a third wiring portion covering an inner wall of the first recessed portion, and a via which runs through the base member from the front surface to the rear surface; and the via electrically connects the first wiring portion, the second wiring portion and the third wiring portion to each other, wherein the via is in direct contact with the first wiring portion, the second wiring portion and the third wiring portion.