In a radiation detecting apparatus of the invention, plural pixels are arranged, and the pixel has a conversion element converting a radiation into an electric signal and a switching element connected to the conversion element. The conversion element includes a first electrode disposed on a first surface of an insulating substrate, a second electrode disposed on the first electrode, and a semiconductor layer disposed between the first electrode and the second electrode. The first electrode is made of a light-transmitting conductive material which transmits light emitted from a light source, and the first electrode is formed form a light transmitting electroconductive material transmitting light emitted form a light source disposed on a second surface of the insulating substrate opposite to the first surface. The switching element has a light shielding member which prevents incidence of the light from the light source to the switching element.