A radiation imaging apparatus (100) is provided. The apparatus (100) comprises a plurality of pixels (200) each including a conversion element (202) and a switch (201), a driving circuit (214) configured to control the switches (201) via drive lines (Vg), a bias power supply unit (104) configured to supply a bias potential to the conversion element (202) via a bias line (Bs), column signal lines (sig) to which signals are output from the plurality of pixels (200), and a detection unit (106). The plurality of pixels (200) include a first pixel (200a) and a second pixel (200b), which are adjacent to each other in the row direction and are connected to a common column signal line (sig). The switch (201) of the first pixel (200a) and the switch (201) of the second pixel (200b) are connected to drive lines (Vg) different from each other. The detection unit (106) determines presence/absence of radiation irradiation based on a current flowing to the bias line (Bs).