A timing signals generator, a frequency divider, an oscillator, and a signals processing IC generates driving signals and transfer signals of a CCD. When the CCD is exposed through a long time exposure in which exposure is performed for not less than a predetermined time, each of a clock frequency of driving signals during an exposure period and a clock frequency of each of driving signals and transferring signals during a transferring period is adjusted to be lower than a clock frequency of thereof in an exposure state in which exposure is performed for less than the predetermined time period.