Provided is a radiation irradiation device that can restrict movement of an arm part during device movement without providing a mechanism that becomes a user's obstacle. The radiation irradiation device includes a radiation generation unit that generates radiation; an arm part having one end to which the radiation generation unit is attached; a support member having one end to which the other end of the arm part is connected so as to be rotationally movable; a body part to which the other end of the support member is connected; a leg part that is provided on a bottom surface of the body part and is capable of traveling on a device placement surface; and an arm locking part that restricts the rotational movement of the arm part. The arm locking part is provided inside the arm part.