An apparatus for identifying the state of an object inputs time series images into a first classifier to detect an object region including a predetermined object from each image, determines whether the region of each image is in a mixed state in which the region includes another object other than the object, chronologically inputs characteristics obtained from pixel values of the region of each image into a second classifier having a recursive structure, and applies a recursively used internal state of the second classifier stored in a memory to the second classifier, identifying the state of the object involving time-varying changes in outward appearance. The apparatus rejects the latest internal state when the region of each image is in the mixed state. The apparatus updates the internal state stored in the memory with this latest internal state when the region is not in the mixed state.