PURPOSE: To control a storage time in real time with high accuracy, by adding a detection mechanism of stored electric charge to an electric charge storage section of elements constituting each video element.

CONSTITUTION: When stored charge 6 on a photo electric conversion section 1 is increased according to the intensity of illumination, the potential at a floating gate terminal 8 is increased. As a result, the charge of the storage section is estimated by detecting the potential at a floating gate terminal 8 is increased. As a result, the sharge of the storage section is estimated by detecting the voltage change at the terminal 8. In this device, the storage time of each element is controlled with this detection signal. Thus, since no increase/decrease of the charge is present, no harmful influence is induced on the uneven sensitivity of sensor output, etc.