To provide a long-life excimer lamp capable of keeping very strong excimer emission output without moving to arc discharge even if high-frequency power inputted to the lamp is increased without needing a radio-frequency power supply (RF power supply) having a high output voltage.

This excimer lamp is is provided with a discharge vessel discharged by using radio-frequency discharge (RF discharge) and filled with a rare gas around 60-200 kPa, and a pair of external electrodes; and is so structured as to discharge it by using the radio-frequency power supply (RF power supply) having a frequency of 1-100 MHz; and a pair of the external electrodes are both formed into a linear or dot-like shape. The excimer lamp is so structured as to be mounted on an irradiation device to form a resonance circuit by serially inserting a choke coil between the excimer lamp and the radio-frequency power supply.