Abstract: The invention relates to an irradiating device, especially for irradiating with ultraviolet light substrates which are provided with a coating that can be cured using ultraviolet light. The inventive device comprises a longitudinally extending radiation source (12) which is provided for emitting ultraviolet and/or visible electromagnetic radiation, which is arranged in a housing (10) between a reflector (18) and a housing opening (14) that can be aligned with an object (16) to be irradiated, and which is preferably configured as a tubular mercury discharge lamp. The inventive device also comprises a cooling system (20) for dissipating the waste heat generated by the radiation source (12). The aim of the invention is to create a compact modular construction and, optionally, an oxygen-reduced illumination zone.