1. A learning device comprising: a feature-quantity extraction unit for extracting a feature quantity from a feature point of a learning image with respect to each of a plurality of learning images including a learning image including a detection target and a learning image not including the detection target; a weak-classification calculation unit for calculating a classification result of the detection target according to a weak classifier for every learning image by substituting the feature quantity corresponding to the weak classifier into the weak classifier with respect to each of a plurality of weak classifiers constituting a transfer classifier, which is a classifier for detecting the detection target obtained by statistical learning; and a classifier generation unit for generating the classifier for detecting the detection target using the weak classifier selected from the plurality of weak classifiers on the basis of the classification result.