n the thickness of the adhesive layer 34 is determined by considering such variations as above, though the adhesive layer 34 may be pushed from the groove 41A when the first light emitting device 10 is inserted in the groove 41A, the pushed portion of the adhesive layer 34 is held in the side groove 41B. Therefore, there is no risk that the adhesive layer 34 is electrically contacted to a lead ele