Abstract: A synchronized moving radiation shield apparatus includes at least one shielding block disposed under a radiation pathway of a radiation therapy unit in such a manner that a radiation field is formed with the shielding block, wherein an affected portion of a person is exposed to radiation through the radiation field while radiation therapy of a portion, other than the affected portion, of the person, is shielded by the shielding block. The apparatus further includes a movable portion for movably holding the shielding block while not blocking the passing of radiation through the radiation field; drive means, connected to the movable portion, for moving the radiation field to a specific position; and control means for controlling the drive means in such a manner that the radiation field is movable in matching to a variation in position of the affected portion.