A radiation detector attaching and detaching device, for a radiation detecting apparatus having a plurality of radiation detectors for detecting radiation and a radiation detector stand for respectively maintaining the radiation detectors in trenches arranged with a predetermined interval. The radiation detector attaching and detaching device has a pair of rotational jigs abutting against projections provided at both sides of each of the radiation detectors maintained in the radiation detector stand; and a pair of rotational members configured to be freely rotatable, the rotational members comprising the rotational jigs.