An imaging device uses a solid state imaging element, during multi-field
accumulation to prevent shading and oscillatory phenomena such as
repeated black and white patterns. A signal is supplied from a timing
signal generation circuit to switches, and controls the ON/OFF operation.
During the H period of the signal, the switch is closed, and the output
value of an amplifier is input to a capacitor. During the L period of the
signal, the switch is opened, and the average value of the output of the
amplifier is maintained in the capacitor. During the H period, the switch
is open, while during the L period, the switch is in the ON state. At
this time, the level of the capacitor C2 and the output of the amplifier
are input to an amplifier, and their difference is amplified and supplied
to a capacitor C3 via the switch.