Radiation detection device

A radiation detection device comprising:

• a detecting element group in which a plurality of detecting elements that detect radiation are three-dimensionally arranged,
• wherein the detecting element group has a structure provided with a depletion formed by removing the detecting element at any position from a virtual detecting element group in which the detecting elements are laid out on any virtual surface,
• wherein the virtual surface includes a first virtual surface and a second virtual surface, the second virtual surface being opposed to the first virtual surface,
• wherein the detecting element group includes a first detecting element group arranged on the first virtual surface and a second detecting element group arranged on the second virtual surface, and
• wherein the first detecting element group and the second detecting element group include respective first detecting elements arranged at mutually different positions viewed in a normal direction of the first virtual surface and the second virtual surface, and at least a second detecting element of the first detecting element group is arranged in a same position in the normal direction as another detecting element of the second detecting element group.