1. An image processing apparatus comprising: image clipping means for clipping a window image from a predetermined position of an original image; feature extracting means for extracting a feature value of the window image on the basis of a predetermined criterion; candidate identifying means for determining, on the basis of the feature value, whether the window image satisfies a predetermined condition for a candidate including a detection target irrespective of whether the window image includes the detection target; and detecting means for confirming whether the same window image includes the detection target if the window image satisfies the predetermined condition.