A radiation image capturing system includes the following. A radiation irradiating apparatus irradiates the radiation image capturing apparatus according to control by a generator. A control device transmits an external synchronizing signal to the radiation image capturing apparatus, transmits an irradiating request signal to the generator, and synchronizes the radiation image capturing apparatus with the radiation irradiating apparatus. When the external synchronizing signal is received, the radiation image capturing apparatus switches the control mode. After the control mode is switched, the radiation image capturing apparatus starts a readout process of the image data at a timing delayed a predetermined amount of time from a timing that the external synchronizing signal is received. The control device transmits the irradiating request signal to the generator at a timing delayed a predetermined amount of time from a timing that the irradiating request signal should be transmitted to the generator.
