LIGHT-EMITTING DEVICE AND PHOSPHOR

A light-emitting device is disclosed which can emit light with high intensity by using a phosphor containing a rare earth ion complex with excellent durability. A phosphor used in such a device is also disclosed. The light-emitting device is characterized by comprising a semiconductor light-emitting element which emits light in the range from the near-ultraviolet to the visible and a phosphor containing a rare earth ion complex which has an aromatic ring, contains a Brφnsted acid ion having a pKa value of not more than 7 as a ligand, and produces light when illuminated with the light from the semiconductor light-emitting element.