To simultaneously image a plurality types of tracer molecules for a Compton image and a PET image. Provided is an imaging device comprising: a first Compton camera (10) for receiving one gamma ray emitted from an imaging target (900) administered by first probe having positron emitting nuclei and second probe having gamma ray emission nuclei; and a second Compton camera (20) which is arranged opposite to the first Compton camera (10) and receives another gamma ray emitted from the imaging target (900). The imaging device is also provided with: an imaging processor for distinguishing and reconstructing a PET image and a Compton image in accordance with the combination of the Compton cameras which detected the gamma rays; and a display for displaying the PET image and the Compton image in association respectively with the first and the second probes.