1. A learning apparatus that determines a weight using neural-network-based learning, the weight being used to generate a subject map for specifying a region of a subject on an image, comprising: information map generating means for extracting a feature value of a feature of the region of the subject from a learning image that includes the subject and that is used for the learning, and generating an information map representing the feature value in each region of the learning image; subject map generating means for generating the subject map by performing weighted addition of, using the weight, the plurality of information maps representing the feature value of the feature, which are different from each other; weight change amount calculating means for calculating an amount of change by which the weight is to be changed using the subject map and an image label that is determined in advance and that represents the region of the subject in the learning image; and updating means for adding the amount of change to the weight and updating the weight.