To stably extract an object even when the object is somewhat hidden or the direction of the object is fluctuated without utilizing any shape information by collating the object while utilizing the local color histogram of attentional area, and repeating this processing while changing its position or the like.

In an object learning device 1, an object area extracting device 4 extracts the area of the object from the image of a registered object while using a window function, etc., and a color histogram preparing device 5 calculates the color histogram to be used as a dictionary on the stage of recognition while using the picture elements in the extracted partial area. At an object retrieving device 2, the partial image in the specified area (concerned area) is extracted while using the same window function as the time of learning and the color histogram is calculated while using the color values of these picture elements. The color histograms are successively calculated while scanning the concerned areas and further, this processing is repeated while changing the size of the input image. Then, a distance measuring instrument 10 calculates the value of distance with the histogram at the time of learning, and when that value is less than a certain threshold value, the area is defined as the learnt object.