1. An emotion recognition apparatus that recognizes an emotion of a speaker from an input speech, comprising: a characteristic tone detection unit operable to detect, in the input speech, a characteristic tone that relates to a specific emotion; a speech recognition unit operable to recognize types of phonemes included in the input speech, based on the characteristic tone detected by said characteristic tone detection unit; a characteristic tone occurrence indicator computation unit operable to compute a characteristic tone occurrence indicator for each of the phonemes, based on the types of the phonemes recognized by said speech recognition unit, the characteristic tone occurrence indicator indicating a likelihood of the phoneme being spoken with the characteristic tone; and an emotion judgment unit operable to judge an emotion of the speaker in a phoneme at which the characteristic tone occurs in the input speech, using the characteristic tone occurrence indicator computed by said characteristic tone occurrence indicator computing unit, in accordance with a rule that the specific emotion is stronger when the characteristic tone occurrence indicator is smaller.