To provide a light-emitting device that stores generated power in a storage battery and lights a luminous source by using the power supply from the storage battery, in which the power of a power storage unit enables light emission over a prolonged period of time while having good visibility.

The light-emitting device includes a solar battery 2, a chargeable/dischargeable power storage unit 3, a display unit 5 where light-emitting diodes (light emitters) 4 capable of emitting light by the power supply from the power storage unit 3 are arranged regularly at predetermined positions, a charge/discharge control unit 7a controlling the charge and discharge of the power storage unit 3, and a power storage amount calculating unit 7b that calculates the stored power amount in the power storage unit 3. The size of a light-emitting area of a light-emitting unit 5 can be changed according to the stored power amount of the power storage unit 3.