PROBLEM TO BE SOLVED: To provide a radiation image photographing system and a radiation image photographing device capable of efficiently obtaining a radiation image of proper image quality.SOLUTION: Controlling means 22 of a radiation image photographing device 1 is configured to carry out reset processing for resetting a radiation detecting element 7 by discharging an electric charge from the radiation detecting element 7 during radiation image photographing processing, transit to an electric charge accumulation mode accumulating the electric charge in the radiation detecting element 7 when at least minimum reset time has passed, and transit to a read-out mode discharging the electric charge from the radiation detecting element 7 and making a read-out circuit 17 carry out image data read-out processing when predetermined accumulation time has passed. The controlling means 22 is configured to carry out the reset processing during dark image obtaining processing, transit to the electric charge accumulation mode when predetermined reset time has passed and standby while preventing the irradiation of radiation, and transit to the read-out mode when predetermined standby time has passed. The minimum reset time is time decided in advance according to the accumulation time.
