To provide a radiation imaging apparatus which is capable of both connecting state radiographing for radiographing with a C arm connected and non-connecting state radiographing for radiographing with the C arm disconnected, and is convenient and obtains high quality images, the apparatus includes: a flat panel detector a holding unit for holding at least the flat panel detectorand a control unit for controlling the flat panel detector. With the configuration, the flat panel detector can be connected to and disconnected from the holding unit connecting state radiographing can be performed with the flat panel detector connected to the holding unit, and non-connecting state radiographing can be performed with the flat panel detector disconnected from the holding unit the control unit controls the flat panel detector such that a heat generation quantity of the flat panel detector during the non-connecting state radiographing can be lower than a heat generation quantity of the flat panel detector during the connecting state radiographing.
