1. A radiation detecting element comprising: a plurality of pixels disposed in a matrix in a detection region that detects radiation, each pixel including a sensor portion that generate charges based on irradiation of radiation or on illumination of light that has been converted from radiation, and a switch element for reading out the generated charges; a plurality of first scan lines, connected to the switch elements included in pixels that have been employed as radiographic imaging pixels out of the plurality of pixels, through which control signals for switching the switch elements flows; a plurality of second scan lines, connected to the switch elements included in pixels that have been employed as radiation detection pixels among the plurality of pixels, through which control signals for switching the switch elements flows; and a plurality of signal lines, connected to the switch elements, through which electric signals flows corresponding to the charges that have been generated in the pixels, in accordance with the switching state of the switch elements.