1. An apparatus comprising: an image pickup unit configured to image an object; an object discriminating unit configured to discriminate the object by using a plurality of images captured under a plurality of imaging conditions by the image pickup unit; a discriminable range generating unit configured to generate a discriminable range that is a range of the plurality of imaging conditions under which the object is discriminable by the object discriminating unit; an identification determination result range generating unit configured to generate an identification determination result range that is a range of the plurality of imaging conditions under which the discriminable range generating unit determines the objects are identical; an imaging condition setting rule generating unit configured to generate an imaging condition setting rule that is a rule for setting an imaging condition by using the discriminable range and the identification determination result range; and an imaging condition setting unit configured to set an imaging condition by using the imaging condition setting rule, wherein the imaging condition setting rule generating unit generates an imaging condition setting rule that is a rule for setting an imaging condition by using the discriminable range and the identification determination result range and searches for the imaging condition setting rule that the discriminable range and the identification determination result range overlap, and the imaging condition setting unit sets an imaging condition by using the searched imaging condition setting rule, wherein the imaging condition setting rule is generated based upon a distance and a direction of movement of the identification determination result range that satisfies a predetermined condition.