To precisely control a focus regardless of the type of an original and the feature of an original image.

In a step S2, an AF optical system detects the sharpness of the image of a film formed on the image pickup face of CCD. In a step S3, a color component optimum for detecting sharpness is decided as an optimum condition for detecting sharpness based on the result. In a step S4, a focus is controlled while the sharpness of the image of the color component is detected.