Abstract: It is described an irradiation device (10; 100) of a paste-type composition (C) comprising a container body (12; 120) equipped with a longitudinal through opening (14; 140), for the transit of the paste-type composition (C) to be irradiated, and with a dispensing head (18; 180) extending from the longitudinal through opening (14; 140); at least one irradiation element (24; 240) arranged in the container body (12; 120) and suitable for irradiating the paste-type composition (C) in transit in the longitudinal through opening (14; 140); and an energy source (26; 260) also arranged in the container body (12; 120) and in electrical connection with the at least one irradiation element (24; 240). It is also described a cartridge (50) for application on a treatment site of a paste-type composition (C) to be irradiated, the cartridge comprising a tube (30; 300) of paste-type composition (C) able be removably associated with such a irradiation device (10; 100).