Provided is a light emitting device including: a base material mounted on a wiring substrate; a light emitting element array provided on the base material; a first conductive pattern provided on the surface of the base material, the first conductive pattern including a first facing region connected to the light emitting element array, the first facing region being along a side surface of the light emitting element array and facing to the light emitting element array, and a first extending region extended beyond the first facing region; and penetrating members penetrating the base material from the first conductive pattern to a back surface side of the base material, each penetrating member being connected to the first facing region or the first extending region.