A radiation imaging apparatus comprising: a pixel array including a plurality of pixels arranged in a matrix in which each pixel includes a conversion element arranged to convert radiation into a charge and a first switch element arranged to transfer an electric signal based on the charge; a plurality of wirings arranged in the pixel array; and detecting means arranged to detect radiation irradiation to the pixel array, wherein: the detecting means includes a detecting circuit arranged to detect the radiation irradiation to the pixel array on the basis of a plurality of currents, flowing through the plurality of wirings, detected for each of the plurality of wirings by a current detection circuit, the plurality of wirings connected to each pixel includes a drive wiring configured to supply the first switch element with a signal for controlling a conductive state and a non-conductive state of the switch element, a bias wiring (Vs) configured to supply the conversion element with a voltage for the conversion element to convert the radiation into the charge, and a signal wiring configured to transmit the electrical signal to a readout circuit; characterized in that the current detection circuit is arranged to detect a current flowing through the bias wiring and a current flowing through at least one of the drive wiring and the signal wiring; and the detecting circuit is arranged to detect the radiation irradiation to the conversion element on the basis of the currents detected by the current detection circuit. a pixel array including a plurality of pixels arranged in a matrix in which each pixel includes a conversion element arranged to convert radiation into a charge and a first switch element arranged to transfer an electric signal based on the charge; a plurality of wirings arranged in the pixel array; and detecting means arranged to detect radiation irradiation to the pixel array, wherein: the detecting means includes a detecting circuit arranged to detect the radiation irradiation to the pixel array on the basis of a plurality of currents, flowing through the plurality of wirings, detected for each of the plurality of wirings by a current detection circuit, the plurality of wirings connected to each pixel includes a drive wiring configured to supply the first switch element with a signal for controlling a conductive state and a non-conductive state of the switch element, a bias wiring (Vs) configured to supply the conversion element with a voltage for the conversion element to convert the radiation into the charge, and a signal wiring configured to transmit the electrical signal to a readout circuit; characterized in that the current detection circuit is arranged to detect a current flowing through the bias wiring and a current flowing through at least one of the drive wiring and the signal wiring; and the detecting circuit is arranged to detect the radiation irradiation to the conversion element on the basis of the currents detected by the current detection circuit. the detecting means includes a detecting circuit arranged to detect the radiation irradiation to the pixel array on the basis of a plurality of currents, flowing through the plurality of wirings, detected for each of the plurality of wirings by a current detection circuit, the plurality of wirings connected to each pixel includes a drive wiring configured to supply the first switch element with a signal for controlling a conductive state and a non-conductive state of the switch element, a bias wiring (Vs) configured to supply the conversion element with a voltage for the conversion element to convert the radiation into the charge, and a signal wiring configured to transmit the electrical signal to a readout circuit; characterized in that the current detection circuit is arranged to detect a current flowing through the bias wiring and a current flowing through at least one of the drive wiring and the signal wiring; and the detecting circuit is arranged to detect the radiation irradiation to the conversion element on the basis of the currents detected by the current detection circuit.