1. A learning apparatus comprising: a plurality of detection units configured to detect a part or whole of a target object from a plurality of learning images in each of which an actual state of the target object is known; an estimation unit configured to estimate a state of the target object detected by the plurality of detection units; a classification unit configured to classify the learning images into a plurality of state classes based on the estimated state of the target object; and a calculation unit configured to calculate an error rate of the estimated state of the target object for each of the state classes with respect to each of the plurality of detection units based on the actual state of the target object; a weight determination unit configured to determine a weight with respect to each of the plurality of detection units for each of the state classes based on the calculated error rate; and a storage unit configured to store respective weights for the plurality of detection units in association with the state classes of the target object.