The storage unit 2 disposed on the foot side of the subject placed on the top plate includes a box body including a block-shaped member 22 and a dish-shaped member 23, and a lid body that covers an upper part of the box body. 21. The lid 21 is provided so as to be able to swing about the shaft 20 with respect to the dish-shaped member 23 in the box formed of the block-shaped member 22 and the dish-shaped member 23. When the lid 21 is in the closed state, the lid 21 covers the upper part of the dish 23 in the box composed of the block 22 and the dish 23. In this state, as shown in FIG. 2, the upper surface of the lid 21 and the surface of the top plate in the storage section 2 are arranged at the same height and have the same plane.
