A Pb plate and a base board loading electronic components such as a signal processing circuit and a power supply circuit are disposed on a case side so as to decrease the weight and the thickness of a sensor section. Besides, the case has a mechanical strength enough to support the active matrix substrate without deformation. Further, a small-signal amplifier control substrate and a gate driver control circuit substrate are inserted inside the case through slits and electrically connected to the electronic components loaded on the base board.