1. A learning method for pattern recognition, comprising: an image input step of inputting an aggregation of different types of object image data; a local feature detection step of detecting local features that have given geometric structures from each object image data inputted in the image input step; a clustering step of performing clustering on the local features detected in the local feature detection step; a feature selection step of selecting plural representative features based on results of the clustering in the clustering step; and a learning step of learning for recognition or detection of an object that corresponds to the object image data with the use of a learning data set, which contains as supervisor data the representative local features selected in the feature selection step.