A CPU calculates integrating values of image-capturing signals in a band 1 obtained by removing through a band pass filter a low frequency component of image-capturing signal output from an image-capturing device and integrating values of the image-capturing signals in a band 3 retaining the low frequency component intact, each calculated in correspondence to one of a plurality of lens positions. The CPU then obtains focal point evaluation values based upon these integrating values in correspondence to the individual bands. In addition, when it is judged that the image-capturing signals are saturated, the CPU calculates a new evaluation value parameter 1 history record=(focal point evaluation value history record in band 3-focal point evaluation value history record in band 1). The CPU then determines a new evaluation value parameter 1 history record extremal value through a 3-point interpolation operation and calculates a lens position corresponding to the extremal value.