[Problem] To separate biological patterns more efficiently and effectively.[Solution] An image processing apparatus according to the present invention is characterized by comprising: an image obtaining means for obtaining an image in which a first biological pattern and a second biological pattern having different textures are superimposed; a normalizing means for normalizing density of the image on the basis of an average and a standard deviation of pixel values inside a local region in the image using a parameter in accordance with difference in texture between the first biological pattern and the second biological pattern to thereby separate the first biological pattern and the second biological pattern in the image; and a pattern collating means for collating a known pattern for collation with each of the first biological pattern and the second biological pattern separated by the normalizing means.