A radiographic image capturing apparatus comprising: a plurality of radiation detecting elements arranged two-dimensionally; a plurality of signal lines each connected to a radiation detecting element; a readout IC equipped with a plurality of readout circuits connected to the signal lines, respectively; a power source circuit which supplies a power to the readout IC; and a bias power source which applies a reverse bias voltage (Vbias) to the radiation detecting elements, wherein the radiographic image capturing apparatus is configured so that an imaging mode can be switched at least between (i) a wake up mode in which the power is supplied to at least one functional section so that an imaging can be performed, and (ii) a sleep mode in which the power is supplied to a required minimum functional section of the functional section and the imaging cannot be performed, and the bias power source applies the reverse bias voltage (Vbias) to the radiation detecting elements in the sleep mode such that electric charges remaining in the radiation detecting elements flow out toward the bias power source, and wherein the bias power source is configured to gradually increase the voltage level from the reverse bias voltage level until the voltage applied from the bias power source to the radiation detecting elements reaches a set threshold (Vth), said threshold having a voltage level greater than the reverse bias voltage (Vbias), wherein the bias power unit applies the reverse bias voltage (Vbias) to the radiation detecting elements only for a predetermined time (Δt), such that the voltage applied rises and falls between the reverse bias voltage (Vbias) and the threshold (Vth). a plurality of radiation detecting elements arranged two-dimensionally; a plurality of signal lines each connected to a radiation detecting element; a readout IC equipped with a plurality of readout circuits connected to the signal lines, respectively; a power source circuit which supplies a power to the readout IC; and a bias power source which applies a reverse bias voltage (Vbias) to the radiation detecting elements, wherein the radiographic image capturing apparatus is configured so that an imaging mode can be switched at least between (i) a wake up mode in which the power is supplied to at least one functional section so that an imaging can be performed, and (ii) a sleep mode in which the power is supplied to a required minimum functional section of the functional section and the imaging cannot be performed, and (i) a wake up mode in which the power is supplied to at least one functional section so that an imaging can be performed, and (ii) a sleep mode in which the power is supplied to a required minimum functional section of the functional section and the imaging cannot be performed, and the bias power source applies the reverse bias voltage (Vbias) to the radiation detecting elements in the sleep mode such that electric charges remaining in the radiation detecting elements flow out toward the bias power source, and wherein the bias power source is configured to gradually increase the voltage level from the reverse bias voltage level until the voltage applied from the bias power source to the radiation detecting elements reaches a set threshold (Vth), said threshold having a voltage level greater than the reverse bias voltage (Vbias), wherein the bias power unit applies the reverse bias voltage (Vbias) to the radiation detecting elements only for a predetermined time (Δt), such that the voltage applied rises and falls between the reverse bias voltage (Vbias) and the threshold (Vth).