PROBLEM TO BE SOLVED: To provide a radiation imaging system capable of suppressing power consumption in detection processing when detecting irradiation start of radiation in a radiation imaging apparatus itself.SOLUTION: The radiation imaging system 50 includes: the radiation imaging apparatus 1 having a control means 22 for detecting the irradiation start of the radiation on the basis of leak data dleak read before radiation imaging a first trigger input means 58 for inputting signals for starting reset processing of each radiation detection element 7 to the radiation imaging apparatus 1 and a second trigger input means 58 for inputting signals for starting the read processing of the leak data dleak before the radiation imaging. The control means 22 of the radiation imaging apparatus 1 makes the reset processing of each radiation detection element 7 be started when the signals are received from the first trigger input means 58, and makes the read processing of the leak data dleak before the radiation imaging be started when the signals are received from the second trigger input means 58.
