To provide an electron beam irradiation apparatus, capable of being simplified without the need for laying gas piping in an X-ray shielding area and performing the work of replacing the electron beam discharge tube, without the need for a worker to put hands into the X-ray shielding area, when the electron beam discharge tube is replaced.

A cooling gas inlet part is provided above a head part at a location outside the X-ray shielded zone of the electron beam irradiation apparatus. The head part of the electron beam discharge tube comprises an air-cooled body, in which the mechanism for cooling an irradiation window is embedded; a head body, in which the air-cooling body is fastened to its one end and which has an inlet for a cooling gas from the outside of the electron beam discharge tube; and an airtight body, provided in between the air-cooled body and the head body for a rigid inner wall and the periphery of the inner wall. By fastening the air-cooled body to the head body, an air-cooled path which is continuous from the cooling gas inlet to the irradiation window is formed.