A sensor lower electrode of a MIS type photosensor is connected to a gate line distributed in a next line in a scanning direction through a refreshing capacitor. The MIS type photosensors of an (n-1)-th line are refreshed on the basis of an ON/OFF operation of TFTs accompanying a reading operation for a pixel column of an n-th line to thereby allow the refresh operation to be carried out every scanning line. Thus, it is possible to prevent a moving image from becoming unnatural due to the refresh operation as in the background art.