PURPOSE: To perform the satisfactory AF operation even in the case that an optical system is out of focus very much.

CONSTITUTION: The image of camera incident light from a pickup object is formed by the optical system including a focus lens 2 driven by a stepping motor (lens driving circuit) 1 and is inputted to an image pickup element 3. The output of the image pickup element is subjected to normal preprocessing by a preamplifier or the like and is converted by an A/D converter 4 and is supplied to not only a camera circuit 5 but also a filtering circuit 6. The filtering circuit 6 divides the input signal into 8 bands f0 to f7 and outputs them. Respective filtering outputs are rectified by a rectifier and integrator and are integrated in a prescribed area of the picture in the same filed and are converted to focus evaluation vectors P (p0 to p7) and are supplied to a microcomputer 7. The microcomputer generates a focus lens control signal based on focus evaluation vectors P and supplies it to the stepping motor. The focus lens 2 is moved in the direction of the optical axis by the stepping motor 1.