A light-emitting device that can switch between two modes: single light emission and intermittent light emission is provided. The light-emitting device includes a driver circuit that can supply a control pulse signal, a constant current power supply that is supplied with the control pulse signal and can supply a constant current pulse, and a light-emitting panel that is supplied with the constant current pulse. The driver circuit includes a start switch circuit that can supply a start signal, a pulse-interval modulation circuit that can supply a pulse-interval modulation signal, and a microcomputer that is supplied with the start signal and the pulse-interval modulation signal and can supply the control pulse signal.