To reduce the scale of a circuit and power consumption and also to obtain a practical contrast evaluation value by sharing the circuit.

A band-pass filter for performing outline emphasis processing and a band-pass filter for detecting the contrast evaluation value of autofocusing control are used as band-pass filters 24a, 24b,... in common. Thus, the scale of the circuit can be reduced. Besides, a random number counter is used in processing needed in the case of obtaining the contrast evaluation value, and sampling data used in finding the evaluation value is thinned out at random. Thus, the contrast evaluation value can be efficiently formed.