A signal processing device includes: a basis storage that stores an acoustic event basis group; a model storage that stores an identification model, as a feature amount, a combination of activation levels of spectral; an identification signal analysis unit that, upon input of a spectrogram of an acoustic signal for identification, performs sound source separation on the spectrogram by using a spectral basis set that is obtained by appending spectral bases corresponding to an unknown acoustic event that is an acoustic event other than the acoustic event specified as a detection target to the acoustic event basis group and causing only unknown spectral bases within the spectral basis set to be learned, and thereby calculating activation levels of spectral bases of the acoustic events in the spectrogram of the acoustic signal for identification; and a signal identify unit that identifies an acoustic event included in the acoustic signal for identification.