Abstract: In an optical device such as an optical sensor or a solid-state imaging device having a photodiode for receiving light and producing photocharges and a transfer transistor (or an overflow gate) for transferring the photocharge, it is configured that photocharges overflowing from the photo diode in storage operation are stored into a plurality of storage capacitance elements through the transfer transistor or the overflow gate, thereby obtaining the optical device adapted to maintain a high sensitivity and a high S/N ratio and having a wide dynamic range.