1. A radiation image sensing apparatus comprising an image sensor configured to sense a plurality of radiation images at a frame rate according to a synchronization signal, and a controller configured to control the image sensor, wherein in a case in which the frame rate is lower than a predetermined frame rate, the controller causes the image sensor to perform a temperature controlling operation of generating additional heat other than heat generated by an image sensing operation in addition to the image sensing operation so as to reduce a change in a temperature of the image sensor.