A radiation detecting apparatus capable of obtaining good images including decreased noise includes a plurality of pixels, each having a photoelectric conversion element for converting incident radiation into an electric signal and a first switch element, connected to the photoelectric conversion element, and a second switch element, not connected to the conversion element. A first signal line, a second signal line and a drive line are provided, where the first switch element has a first main electrode connected electrically to the first signal line, a second main electrode connected electrically to the photoelectric conversion element, and a gate electrode connected electrically to the drive line, and the second switch element has a first main electrode connected to the second signal line and a gate electrode connected electrically to the drive wiring common to the first switch element, and a differential means for outputting a signal corresponding to a difference between outputs from the first and second switch elements.