An optical inspection apparatus irradiates a light beam onto the outer surface of an object to be inspected, in the form of an illumination spot having an illumination intensity which is higher in the outer peripheral part of the object to be inspected than in the inner peripheral part thereof while uniformly maintains a temperature rise caused by the irradiation of the light beam, over the outer surface of the object to be inspected, in order to prevent the effective entire signal value of a scattered light signal from lowering, without lowering the linear speed of a movable stage for the object to be inspected in the outer peripheral part of the object to be inspected, thereby it is possible to prevent lowering of the detectability for a foreign matter or a defect, for preventing lowering of inspection throughput.