To improve the dynamic range of the output signal of a CCD image sensor.

An exposure period from the completion of an electronic shutter operation performed in an STTRG pulse 22 to the start of frame shift is divided into two periods by a WTTRG pulse 26. Signal charges accumulated in an odd row in a prior first exposure period A are vertically transferred to an adjacent even row at the timing of the WTTRG pulse 26 and they are mixed. In the odd row and the even row, exposure is performed only in a second exposure period B and the charges are vertically transferred. In a horizontal CCD shift register, the odd row and the even row are mixed and added. They are horizontally transferred and are outputted from the CCD image sensor.