A radiation image pick-up apparatus includes a conversion element, accumulation element, read element, detection element, driving circuit, and controller. The conversion element converts radiation into an electrical signal. The accumulation unit accumulates the electrical signal converted by the conversion element. The read unit reads out the electrical signal accumulated in the accumulation unit. The detection element detects the start and end of irradiation of the radiation. The driving circuit accumulates the electrical signal in the accumulation element responsive to the detection of start of irradiation of the radiation, and drives the read element responsive to the detection of the end of irradiation of the radiation, based on the detection result of the detection element. The controller controls the driving circuit. A radiation image pick-up system is also disclosed.