First and second masts of a stacker crane are arrayed in an X direction and extend vertically. Connecting plates are mounted at lower portions and on both side surfaces, facing a Y direction, of the first and second masts, each including an upper portion fixed to the first or second masts, and a lower portion whose width in the X direction is greater than that of the upper portion. First and second lower hollow frames include a pair of hollow members disposed on both sides of the first and second masts in the Y direction and extending in the X direction and are fixed to the lower portions of the connecting plates. Travelling wheels are supported by the connecting plates and roll on a lower guide rail.