PURPOSE: To prevent occurrence of malfunction by providing a reference area to plural positions, detecting a comparison area with the highest correlation for each reference area, and revising the detection area of a video image based on position information of the comparison area with the highest correlation among the detected comparison areas.

CONSTITUTION: A digitized data by an A/D converter circuit 1 from a video signal is inputted to a 1st correlation detection means D1 and a 2nd correlation detection means D2. The 1st correlation detection means D1 detects the correlation with respect to an upper left reference area K1 and the 2nd correlation detection means D2 detects the correlation with respect to a lower right reference area K2. A correlation comparator 13 compares a minimum integration value of both the data storage circuits, regards the smaller minimum integration value, that is, the position data with a high correlation as a more correct position data and a position data selection circuit 14 gives the position data to a directivity control means 15.