1. An image pick-up apparatus for picking up an image of an object, the image pick-up apparatus comprising: an image pick-up unit having a light receiving surface configured to receive light from the object to carry out photo-electric conversion, and adapted to output a pixel value obtained as the result of the photo-electric conversion; an evaluator configured to evaluate the pixel value; a controller configured to control, in pixel units, exposure time with respect to the light receiving surface on the basis of the evaluation by the evaluator; a storage unit configured to store plural pixel values output from the image pick-up unit and the exposure times of pixels corresponding to the plural pixel values, the plural pixel values included in a frame or a field, and an exposure time of a particular pixel may be different than an exposure time of another pixel; and a correcting unit configured to correct the plural pixel values stored in the storage unit based on the exposure times stored in the storage unit, wherein the controller is operative so that when the pixel value is a first predetermined value or more, the controller shortens the exposure time with respect to the pixel of the light receiving surface corresponding to that pixel value, and wherein the controller is operative so that when the pixel value is less than a second predetermined value, the controller elongates the exposure time with respect to the pixel of the light receiving surface corresponding to that pixel value.