1. An image identification device that learns in advance a separating plane used for classifying images into predetermined categories in a feature quantity space using a feature of the image as a coordinate axis and uses the separating plane to classify block images obtained by dividing a target image into the categories, the image identification device comprising: an input unit that inputs the target image; a block image generation unit that divides the target image into a plurality of blocks to generate the block images; a feature quantity computing unit that computes feature quantities of the block images; and a category determination unit that determines whether the block images are classified into one of the categories or not, using the separating plane and coordinate positions corresponding to magnitudes of feature quantities of the block images in the feature quantity space, wherein the feature quantity computing unit uses, as a feature quantity of a given target block image in the block images, local feature quantities calculated according to image information of the target block image and a global feature quantity calculated according to image information of the target image.