The present invention provides a speech recognition device includes a threshold value candidate generation unit which extracts a feature indicating likeliness of being speech from a temporal sequence of input sound, and generates a plurality of threshold value candidates for discriminating between speech and non-speech; a speech determination unit which, by comparing the feature indicating likeliness of being speech with the plurality of threshold value candidates, determines respective speech sections, and outputs determination information as a result of the determination; a search unit which corrects each of the speech sections represented by the determination information, using a speech model and a non-speech model; and a parameter update unit which estimates a threshold value for determining a speech section, on the basis of distribution profiles of the feature respectively in utterance sections and in non-utterance sections, within each of the corrected speech sections, and makes an update with the threshold value.