1. An object identification apparatus which identifies a class of a plurality of registered classes to which an object included in an input image belongs, comprising: a registration unit configured to register in a storage unit a plurality of registered images used in identification of an input image; a holding unit configured to hold designation data required to designate partial areas used in identification; an identification unit configured to extract feature amounts of the partial areas designated by the designation data from the input image and each of the plurality of registered images, and to identify a class to which the input image belongs based on the extracted feature amounts; a registration update unit configured to update registered contents in said storage unit; an update determination unit configured to determine based on the plurality of registered images registered in said registration unit whether or not to require to update processing contents of said identification unit; and a content update unit configured to update, when said update determination unit determines that the processing contents are required to be updated, the designation data held by said holding unit based on registered images registered in said storage unit.