1. An object recognition apparatus comprising: an obtaining unit configured to successively obtain images; an extraction unit configured to extract a partial region from an image obtained by the obtaining unit and extract a feature amount from the partial region; a recognition unit configured to recognize whether the partial region is an image of a target object based on the extracted feature amount and one of a first recognition model and a second recognition model, the first recognition model including a feature amount of a positive example indicating the target object and a feature amount of a negative example indicating a background of the target object, and the second recognition model including a feature amount of the positive example and a feature amount of the negative example set in advance; an updating unit configured to, in accordance with a result of the recognition, update the first recognition model by adding the extracted feature amount to the positive example if the partial region is recognized as being the image of the target object, and adding the extracted feature amount to the negative example if the partial region is not recognized as being the image of the target object; and an output unit configured to output an object region recognized as being the image of the target object, wherein the recognition unit performs recognition on a current image based on the first recognition model including the updated feature amount of the negative example if the object region has been output for a previous image obtained by the obtaining unit, and performs recognition on the current image based on the second recognition model including the feature amount of the negative example set in advance if the object region has not been output for the previous image.