The present invention provides an image processing apparatus capable of preventing deterioration of judgment accuracy when performing document matching process. To be more specific, when selecting feature points in the neighborhood of a target feature point, a predetermined number of feature points are selected after excluding a prespecified number of feature points in turn from the feature point nearest to the target feature point. For example, when the plurality of feature points are selected, the plurality of feature points, after excluding at least a feature point existing at a position nearest to the target feature point, are selected. Thereby, without increasing the amount of feature points for calculation of features (feature vectors), it is possible to prevent the deterioration of judgment accuracy.