A radiation image capturing apparatus is provided with a scanning drive unit which sequentially applies ON voltage to respective scanning lines during a readout process to read out image data from radiation detection elements. From the time before radiation imaging, a controller controls the scanning drive unit to sequentially apply the ON voltage to the respective scanning lines and executes the readout process for the image data from the radiation detection elements. The controller detects start of the radioactive irradiation when the image data exceeds a threshold value, and controls that ON time, during which the ON voltage is applied to the scanning lines from the scanning drive unit during the readout process for the image data before radiation imaging, becomes longer than ON time during a readout process for the image data after finishing the radioactive irradiation.
