1. A weak hypothesis generation apparatus for generating a weak hypothesis for estimating whether provided data is a detection target or not by using a data set including plural learning samples, each of which has been labeled as a detection target or non-detection target, the weak hypothesis generation apparatus comprising: a selection unit for selecting a part of plural hypotheses and selecting one or plural weak hypotheses having higher estimation performance than others with respect to the data set of the selected part of the hypotheses, as high-performance weak hypotheses; a new weak hypothesis generation unit for generating one or more new weak hypotheses formed by adding a predetermined modification to the high-performance weak hypotheses, as new weak hypotheses; and a weak hypothesis selection unit for selecting one weak hypothesis having the highest estimation performance with respect to the data set, from the high-performance weak hypotheses and the new weak hypotheses.