To avoid a decline in the reflectivity of an ultraviolet reflection film caused by lighting for an extended period of time and providing a uniform illuminance an excimer lamp has a silica glass discharge vessel with electrodes on opposite sides of the discharge vessel, wherein excimer discharge is generated in the discharge space of the discharge vessel, wherein an ultraviolet reflection film made of silica particles and alumina particles is formed on a surface exposed to the discharge space and wherein the mean particle diameter of silica particles is at least 0.67 times as large as the mean particle diameter of the alumina particles. The alumina particles in the ultraviolet reflection film preferably constitute at least 5 wt % and more preferably at least 10 wt % of the sum of silica particles and alumina particles.