An image sensing apparatus comprising: image sensing means for sensing an image sensing target to acquire a plurality of sensed images, the image sensing target having a defective portion region; illumination means for illuminating the image sensing target in image sensing by said image sensing means; image sensing condition change means for changing an image sensing condition during sensing the image sensing target; characterized by calculation means for calculating, as an evaluation value, information on a contrast of each of the sensed images acquired by said image sensing means, wherein the evaluation value is calculated based on a ratio of i) a product of a contrast value and an area of the defective portion region and ii) a product of a contrast value and an area of a region other than the defective portion region; first control means for controlling said image sensing condition change means to change the image sensing condition, said image sensing means to sense the image sensing target in parallel with the change of said image sensing condition at every predetermined first step of change of the image sensing condition, and said calculation means to calculate an evaluation value of each of the sensed images; second control means for controlling, after the control by the first control means, said image sensing condition change means to change the image sensing condition within a range where the evaluation value obtained by said first control means changes from increase to decrease, said image sensing means to sense the image sensing target in parallel with the change of said image sensing condition at every predetermined second step of change of the image sensing condition, wherein the predetermined second step is narrower than the predetermined first step, and said calculation means to calculate an evaluation value of each of the sensed images; and image sensing condition setting means for setting the image sensing condition based on the evaluation value obtained by said second control means. image sensing means for sensing an image sensing target to acquire a plurality of sensed images, the image sensing target having a defective portion region; illumination means for illuminating the image sensing target in image sensing by said image sensing means; image sensing condition change means for changing an image sensing condition during sensing the image sensing target; characterized by calculation means for calculating, as an evaluation value, information on a contrast of each of the sensed images acquired by said image sensing means, wherein the evaluation value is calculated based on a ratio of i) a product of a contrast value and an area of the defective portion region and ii) a product of a contrast value and an area of a region other than the defective portion region; first control means for controlling said image sensing condition change means to change the image sensing condition, said image sensing means to sense the image sensing target in parallel with the change of said image sensing condition at every predetermined first step of change of the image sensing condition, and said calculation means to calculate an evaluation value of each of the sensed images; second control means for controlling, after the control by the first control means, said image sensing condition change means to change the image sensing condition within a range where the evaluation value obtained by said first control means changes from increase to decrease, said image sensing means to sense the image sensing target in parallel with the change of said image sensing condition at every predetermined second step of change of the image sensing condition, wherein the predetermined second step is narrower than the predetermined first step, and said calculation means to calculate an evaluation value of each of the sensed images; and image sensing condition setting means for setting the image sensing condition based on the evaluation value obtained by said second control means.