Abstract: A twin-detector type scintillation camera apparatus includes a pair of detectors which is disposed in opposition to each other with a table for supporting an object under examination being interposed therebetween to detect radioactive rays emitted from the object, a rotatable frame disposed in a plane extending in a direction orthogonal to a longitudinal axis of the table and supports the paired detectors at one side thereof, a translation mechanism capable of moving the paired detectors in parallel with each other in a plane extending orthogonally to the longitudinal axis of the object supporting table while maintaining parallelism between the paired detectors, an approaching mechanism which is capable of moving the pair of detectors in directions orthogonal to the directions in which the detectors are moved in parallel with each other, and a rotating mechanism capable of driving rotationally each of the detectors by a predetermined angular distance from a given position.