An index calculating unit calculates a tonality index of a signal component of each area of the input signal transformed into a time frequency domain based on intensity of the signal component and a function obtained by approximating the intensity of the signal component. A similarity calculating unit calculates a similarity between a feature quantity in each area of the input signal obtained based on the index and the feature quantity in each area of the reference signal obtained based on the index calculated on the reference signal transformed into the time frequency domain. A music identifying unit identifies music of the input signal based on the similarity. The present technology can be applied to a music search apparatus that identifies music from an input signal.