PURPOSE: To obtain excellent picture quality by applying A/D conversion to a video signal such as the NTSC or the like so as to obtain a field picture and compensating picture elements so that contour lines by picture elements of the field picture are consecutive.

CONSTITUTION: A video signal input for an even number (odd number) field is A/D-converted by an A/D converter 4 and the result is inputted to a field data interpolation device 5. The interpolation device 5 finds out a contour line E as to a same gradation 100 in dispersion in the even number field and the gradation (100) is imbeded on an odd number line as data for an odd number field component on the contour line. Thus, only one of two fields is in use and a still picture having a scene with a rapid motion is obtained with excellent picture quality.