PURPOSE: To enlarge a dynamic range by driving an image pickup element by the integral multiple of more than 2 of a basic driving frequency, dividing obtained signals into the integral pieces of more than 2, storing them and adding and outputting storage signals for respective fields.

CONSTITUTION: In an image pickup part 10, a CCD 11 is driven by a frequency which is the double of the fundamental driving frequency and only required signals among the obtained signals are turned to digital signals through a correlation double sampling CDS 13 and an A/D converter 15. The signals are stored in memories 19a and 19b and 19c and 19d provided for two pieces each fort an odd numbered field and an even numbered field. The two pieces of the signals stored in the memories are simultaneously read for the respective fields and they are added and outputted by the fundamental driving frequency. Since the signal storage time of the CCD becomes 1/2, a signal level becomes the 1/2 of the case of performing driving by the fundamental driving frequency, however, by performing addition, it is returned to the approximately same level. As a result, the dynamic range of the image pickup element is enlarged apparently.