External electrode discharge lamp and ultraviolet ray irradiating apparatus using the same

Provided are an external electrode discharge lamp and an ultraviolet ray irradiating apparatus using the same wherein a window part (2a) is formed in an end portion of a first electrode (2) and a shielding part (3a) is formed in the corresponding end portion of a second electrode (3), thereby uniformly irradiating ultraviolet rays onto an object, while precisely monitoring from the window part (2a). In an excimer lamp, a first electrode (2) is formed on the upper flat surface of a discharge tube (1), which is a horizontally-longer, rectangular, gastight enclosure made of synthetic quartz and which is sealed with xenon gas therein, and a second electrode (3), which is net-shaped, is formed on the lower flat surface of the discharge tube (1). A net-shaped window part (2a) is formed in an end portion of the first electrode (2) and a shielding part (3a) is formed in an end portion of the second electrode (3) that is opposed to the window part (2a) of the upper-located first electrode (2).