Abstract: For providing a longer lifetime and sensing an image with less noise, there is provided an image sensing apparatus having a flat panel sensor for detecting radiations, a first power circuit for supplying an electric power to the flat panel sensor, a read-out circuit for reading out data of the flat panel sensor circuit, a second power circuit for supplying an electric power to the read-out circuit, and a control circuit for turning the first power circuit on by a first timing signal and for turning the second power circuit on by a second timing signal.