A captured image acquisition section 50 acquires, from an imaging apparatus 12, data of a polarized image obtained by capturing a target object and stores the data into an image data storage section 52. A region extraction section 60 of a target object recognition section 54 extracts a region in which a figure of the target object is included in the polarized image. A normal line distribution acquisition section 62 acquires a distribution of normal line vectors on a target object surface in regard to the extracted region. A model adjustment section 66 adjusts a three-dimensional model of the target object stored in a model data storage section 64 in a virtual three-dimensional space such that the three-dimensional model conforms to the distribution of the normal line vectors acquired from the polarized image to specify a state of the target object.