PURPOSE: To provide a scintilation camera dispensing with prior preparation for data collection, improving resolution by approaching sufficiently to collect data while keeping the predetermined distance between a detector and a testee and allowing the predetermined distance to be maintained by coping adequately with the movement of the testee.

CONSTITUTION: Radioactive isotopes are administered to a testee, and while moving a detector relatively to the testee along the axis of the testee, radiation emitted from the radioactive isotopes is detected to measure the distribution of the radioactive isotopes. A scintilation camera of such constitution is provided with a sensor 15 for detecting that the distance between the detector and the testee reaches the predetermined distance, and approaching/separating means 17, 19 for bringing the detector close to or away from the testee according to the detection result of the sensor 15 so as to inhibit the distance between the detector and the testee from becoming shorter than at least the predetermined distance.