Abstract: Disclosed is a gamma-ray image pickup apparatus having high energy resolution and high position resolution. A Compton camera is constructed by arranging two electrode split planar germanium semiconductor detectors in front and behind. This Compton camera processes a detection signal obtained from an anode and a cathode of the planar electrode split germanium detector, and can measure at how deep position from the detector surface the interaction of a gamma ray occurs. Moreover, with regard to the direction parallel to the electrode surface of the detector, the interaction position of the gamma ray was able to be measured with high accuracy, Accordingly, spatial resolution is improved by resolving a formula for the kinematics of Compton scattering with excellent accuracy.