An electron beam irradiation device comprising: electron beam irradiation means forming an electron beam irradiation zone by generating an electron beam; and gripping/moving means gripping a part of an object to be irradiated which has an upper surface, a lower surface, and a side surface to be irradiated and for moving so that the object to be irradiated passes through the electron beam irradiation zone, wherein the electron beam irradiation means is composed of three electron accelerators (31, 32, 33), and is provided with three irradiation windows (31a, 32a, 33a) located substantially in parallel to these three surfaces to be irradiated, respectively; the irradiation window facing the upper surface or the lower surface of the object to be irradiated among the three irradiation windows has an irradiation width of at least 1⁄2 of the whole width of the upper surface or the lower surface of the object to be irradiated, respectively, the irradiation window facing a side surface of the object to be irradiated among the three irradiation windows has an irradiation width of at least the whole width of the side surface of the object to be irradiated; the gripping/moving means is provided with two gripping mechanisms for gripping different portions of the object to be irradiated alternately, two moving mechanisms for moving the gripping mechanisms in a longitudinal direction, so that the object to be irradiated gripped by the gripping mechanism is passed through the electron beam irradiation zone, and two rotation mechanisms for rotating the gripping mechanisms so that the object to be irradiated gripped by the two gripping mechanisms is rotated. electron beam irradiation means forming an electron beam irradiation zone by generating an electron beam; and gripping/moving means gripping a part of an object to be irradiated which has an upper surface, a lower surface, and a side surface to be irradiated and for moving so that the object to be irradiated passes through the electron beam irradiation zone, wherein the electron beam irradiation means is composed of three electron accelerators (31, 32, 33), and is provided with three irradiation windows (31a, 32a, 33a) located substantially in parallel to these three surfaces to be irradiated, respectively; the irradiation window facing the upper surface or the lower surface of the object to be irradiated among the three irradiation windows has an irradiation width of at least 1⁄2 of the whole width of the upper surface or the lower surface of the object to be irradiated, respectively, the irradiation window facing a side surface of the object to be irradiated among the three irradiation windows has an irradiation width of at least the whole width of the side surface of the object to be irradiated; the gripping/moving means is provided with two gripping mechanisms for gripping different portions of the object to be irradiated alternately, two moving mechanisms for moving the gripping mechanisms in a longitudinal direction, so that the object to be irradiated gripped by the gripping mechanism is passed through the electron beam irradiation zone, and two rotation mechanisms for rotating the gripping mechanisms so that the object to be irradiated gripped by the two gripping mechanisms is rotated.