A radiation-irradiation device comprising: a base ; an arm unit that is mounted on the base and is capable of elongating and contracting in a plan view; a radiation source that is mounted on the arm unit ; and a wheel unit that is mounted on the base and allows the base to travel on a device-placement surface , wherein the wheel unit includes a front wheel unit and at least two rear wheel units that are positioned on a rear side of the front wheel unit in a case in which an elongation direction of the arm unit in the plan view is forward and are away from each other in a direction crossing the elongation direction of the arm unit , each of the rear wheel units includes a wheel that performs traveling rotation for the traveling, and a traveling direction-changing part that changes a direction of the traveling, and each of the rear wheel units further includes first locking means for restraining the traveling rotation of the wheel, and second locking means capable of operating independently of the first locking means and restraining an operation of the traveling direction-changing part; wherein the radiation-irradiation device further comprises an operating portion that includes operating pieces receiving an operating force applied from the outside and operates the first and second locking means, characterised in that each operating piece is a foot pedal; and in that the operating pieces can, in use, be disposed in a first state, in which neither the first locking means nor the second locking means is operated, a second state, in which only the second locking means is operated, and in a third state, in which both the first locking means and the second locking means are operated. a base ; an arm unit that is mounted on the base and is capable of elongating and contracting in a plan view; a radiation source that is mounted on the arm unit ; and a wheel unit that is mounted on the base and allows the base to travel on a device-placement surface , wherein the wheel unit includes a front wheel unit and at least two rear wheel units that are positioned on a rear side of the front wheel unit in a case in which an elongation direction of the arm unit in the plan view is forward and are away from each other in a direction crossing the elongation direction of the arm unit , each of the rear wheel units includes a wheel that performs traveling rotation for the traveling, and a traveling direction-changing part that changes a direction of the traveling, and each of the rear wheel units further includes first locking means for restraining the traveling rotation of the wheel, and second locking means capable of operating independently of the first locking means and restraining an operation of the traveling direction-changing part; wherein the radiation-irradiation device further comprises an operating portion that includes operating pieces receiving an operating force applied from the outside and operates the first and second locking means, characterised in that each operating piece is a foot pedal; and in that the operating pieces can, in use, be disposed in a first state, in which neither the first locking means nor the second locking means is operated, a second state, in which only the second locking means is operated, and in a third state, in which both the first locking means and the second locking means are operated. <EOS>