Disclosed are a radiation image capturing system and a radiation image capturing apparatus. According to one implementation, the radiation image capturing system includes the radiation image capturing apparatus and a console. The detecting unit of the radiation image capturing apparatus detects start of irradiation using a first detecting method in which power consumption amount is small but a capturing condition with which the start of irradiation can be detected is limited, or a second detecting method in which power consumption amount is large but the start of irradiation can be detected under any capturing condition. The console transmits a capturing condition to the radiation image capturing apparatus. The detecting unit selects the first or second detecting method based on the capturing condition, and performs processing of detecting the start of irradiation using the selected detecting method.