To provide an electron beam irradiation device capable of miniaturizing a beam mask, and thereby miniaturizing the whole device.

A control part 9 controls a mask driving mechanism 11 and moves the beam masks 7 on both sides so that the irradiation range of an electron current 3 agrees with the irradiation range L of an irradiation object 8 inputted from an input means 12. The control part 9 also sets, for example, the current amplitude of a chopping wave inputted from a scanning part 10 into a scanner 4 so that the scanning range of the electron current becomes wider to some extent than the irradiation range L of the irradiation object. Thereafter, when an operation key switch on an operation panel is switched, electrons are generated from an electron source 1, and the electrons are accelerated by an accelerator 2, scanned in a prescribed range by the scanner 4, and irradiated only to the tips of the beam masks 7 and the irradiation range L of the irradiation object 8 through a window foil 6 provided on the tip part of a scanning tube 5.