To provide a light-emitting device from which uniform light emission can be obtained by providing an auxiliary wiring; a light-emitting device in which a short circuit between electrodes or between an electrode and an auxiliary wiring, which is attributed to a step caused by the auxiliary wiring, hardly occurs; and a light-emitting device which has high reliability by preventing a short circuit. In an EL light-emitting device including an auxiliary wiring, by covering a step caused by the auxiliary wiring is covered with an insulator, a short circuit between electrodes or between an electrode and the auxiliary wiring, which is attributed to the step caused by the auxiliary wiring, is prevented. Thus, the above objects are achieved.