A radiation irradiation device includes a radiation generation unit an arm part a support member having one end to which the arm part is connected a body part to which the support member is connected and a leg part on which the body part is placed. The leg part includes first casters that are provided on a front side of the leg part and second casters that are provided on a rear side of the leg part. The diameter of wheels of the second casters and is greater than the diameter of wheels of the first casters, and the gravity center position of the entire device is closer to the second casters side than a center between the first casters and the second casters in a state where the arm part is rotationally moved until the radiation generation unit is located at a vertically lowermost position.
