1. A feature parameter candidate generation apparatus for generating feature parameter candidates to be given to a model generation device that builds a model by using a plurality of feature parameters selected from given feature parameter candidates, the apparatus comprising one or more computers; and a storage unit that stores the values of a plurality of kinds of feature parameters extracted from each of a plurality of samples; wherein the one or more computers are configured with: an index value calculation unit that calculates an index value, which is obtained by normalizing the number of the kinds of the values of the feature parameter by the number of the samples, for each feature parameter of the plurality of kinds of feature parameters; an evaluation object selection unit that selects a subset of feature parameters out of the plurality of kinds of feature parameters; an evaluation unit that judges whether the subset of feature parameters selected by the evaluation object selection unit has a desired balance of the index values, by evaluating whether the uniformity of a frequency distribution of the index values satisfies a predetermined criterion; and a candidate determination unit that determines the subset of feature parameters as feature parameter candidates to be given to the model generation device, when the subset of feature parameters is judged to have the desired balance of the index values by the evaluation unit.