PURPOSE: To realize the adjustment with high accuracy in a short time by clipping differentiated output of a contrast picture signal at plural clip levels, obtaining the sum of all image picked-up picture components at each clip output and adjusting an optical axis position in response to the synthesized output of each addition value.

CONSTITUTION: A contrast picture signal AS image picked-up via an optical system 1 to be adjusted is differentiated by a differentiating circuit 5, an absolute value is calculated and then given to clip circuits 6a, 6b to which a different clip level is set. Clip outputs DS1, DS2 clipped by the clip curcuits 6a, 6b are fed respectively to adders 7a, 7b, where the signals are added over the entire area of the contrast picture. Added outputs ES1, ES2 are added mutually at a weight averaging circuit 8, the added synthesis output FS obtained at the circuit 8 is given to a maximum value detecting circuit 9 for detecting the maximum value. As a result, when a maximum value signal GS is produced, a control circuit 10 stops the output of a drive control signal HS to stop the movement of the optical system 1 to be adjusted and the focus adjustment is finished.