PURPOSE: To suppress the rising in the temp. of the upper part of a reflecting body, by a method wherein the part above the upper part of a lamp of the reflecting body is formed into a linear part having a linear cross-section while the part below the upper part of the lamp of the reflecting body is formed into an oval form having an oval cross-section and an exhaust port is provided to the top part of the reflecting body.

CONSTITUTION: Ultraviolet rays and infrared rays are emitted along with the discharge of a high pressure discharge lamp 1 and ultraviolet rays directly transmit a filter 5 from an irradiation opening 3 or are reflected by a reflecting body 2 to transmit said filter 5 from said opening 3 to irradiate an article to be irradiated. Further, a linear part is provided to the upper part of the reflecting body 2 and the distance (a) between the reflecting body and high pressure discharge lamp 1 of an ultraviolet irradiation apparatus is about two times a conventional one and the upper part of the reflecting body 2 is separated from the high pressure discharge lamp 1 and, therefore, an air flow in the reflecting body 2 becomes easy to flow and temp. reducing effect becomes large. From the structural aspect of a housing, the upper final end of the linear part of the reflecting body 2 may have a circular shape.