PURPOSE: To shorten a working time by making it unnecessary to manually fix a footrest and a shoulder pad each time in matching relation to the stature of an examinee, by providing moving means moving in mutually opposite directions in connection with each other at a predetermined speed ratio and a drive means imparting rotational driving force to the moving means.

CONSTITUTION: The footrest 6 provided to the foot positioning part of a top plate 2 is mounted on the block 7 provided so as to be slidable and movable along one side part of the top plate 2 in the longitudinal direction thereof and the lead screw 10 provided to one side part of the top plate 2 in the longitudinal direction thereof is rotationally driven by a motor 14 to move the block 7 having the footrest 6 mounted thereon and a block 9 having a shoulder pad 8 mounted thereto in mutually opposite directions at a speed ratio of 2:1 from the position of L1=2L2 looking from the imaging center 0 of the apparatus. By this constitution, it becomes unnecessary move the footrest 6 and the shoulder pad 8 manually each time in matching relation to the stature of an examinee to fix the same and the fixing time of the examinee can be reduced to about one half of a conventional time.