1. An apparatus for creating a speaker model that represents a distribution of features extracted from a speech of a standard speaker, the apparatus comprising: a first storage unit configured to correspondingly store identification information for identifying each of the speakers and a clean feature representing a feature of a speech of the speaker recorded in a noiseless environment; a second storage unit configured to correspondingly store the identification information and a noisy feature representing a feature of a speech of the speaker recorded in a noisy environment; a transformation-parameter calculating unit configured to calculate a first model parameter indicating a parameter of the speaker model for causing a first likelihood for the clean feature to maximum, and calculates a transformation parameter for causing the first likelihood to maximum, the transformation parameter transforming, for each of the speakers, a distribution of the clean feature corresponding to the identification information of the speaker to a distribution represented by the speaker model of the first model parameter; and a model-parameter calculating unit configured to transform the noisy feature corresponding to the identification information for each of the speakers by using the transformation parameter, and calculates a second model parameter indicating a parameter of the speaker model for causing a second likelihood for the transformed noisy feature to maximum.