An image taking device has a multifocal lens which changes its focal length to change the image taking area on a subject from which an image is to be taken by an image pickup sensor, a distance sensor for measuring the distance to the subject, an image taking distance buffer unit for temporarily storing the image taking distance measured at a past time, a focal length computation unit which computes the focal length of the multifocal lens on the basis of the image taking distance at the present time measured by the distance sensor and the image taking distance supplied from the mage taking distance buffer unit, and a focus control unit which controls the focal length of the multifocal lens so that the focal length of the multifocal lens equals the focal length computed by the focal length computation unit.