A Compton camera device according to the invention includes first means for reading coordinate data of a scattering point of a quantum ray detected by a pre-stage detector for each Compton scattering event, second means for reading coordinate data of a reaching point of the Compton-scattered quantum ray detected by a post-stage detector for each Compton scattering event, and third means for calculating a measurement accuracy of the scattered quantum ray by the first and second means for each Compton scattering event, calculating a statistical quantity of the quantum ray for each calculated measurement accuracy, and outputting the calculated statistical quantity to image reconstruction means.