1. An information processing apparatus for generating a similarity determination algorithm determining a similarity between a pair of data, the information processing apparatus comprising: feature-quantity-extraction expression list generation means for generating a feature-quantity-extraction expression list including a plurality of feature-quantity-extraction expressions, including a plurality of operators, by updating the feature-quantity-extraction expression list of a preceding generation on the basis of an evaluation value of each of the feature-quantity-extraction expressions of the preceding generation; calculation means for inputting first data and second data given as teacher data into each of the feature-quantity-extraction expressions included in the feature-quantity-extraction expression list to calculate a feature quantity corresponding to each of the first data and the second data; evaluation-value calculation means for calculating the evaluation value of each of the feature-quantity-extraction expressions included in the feature-quantity-extraction expression list using the calculated feature quantities and a similarity between the first data and the second data given as the teacher data; and similarity-calculation-expression estimation means for estimating a similarity calculation expression for calculating a similarity between the first data and the second data given as the teacher data using the calculated quantities.