A period of periodical noise caused by a period of a drive signal of a CMOS sensor and a period of a signal generated by driving of a circuit other than the CMOS sensor is acquired, and a length of a horizontal blanking period is adjusted so that one horizontal period of a drive signal of the CMOS sensor becomes an integer multiple of the periodical noise period. Then, column noise is detected from an image signal read out by driving the CMOS sensor with a drive signal based on one horizontal period after the adjustment and the detected column noise is subtracted from the image signal.