1. An image signal processing unit which processes image signals corresponding to an image divided into a plurality of image-areas, comprising: a first detector that detects a sharpness corresponding to how much of said image-area is in focus based on said image signals; a second detector that detects an out-of-focus area, when said sharpness is out of a predetermined permissible range, for said image-area; a blurring processor that carries out a blurring process for an out-of-focus area signal corresponding to said out-of-focus area.