1. A speech recognition method comprising: a step for starting input of speech made by a user in response to a user's operation; a step for determining whether beginning of the input speech is missing; a step for setting pronunciation information for recognizing the input speech of which the beginning is not missing in a case where a head portion of a speech waveform power does not exceed a predetermined threshold value, and setting pronunciation information for recognizing the input speech of which the beginning is missing in a case where the head portion of the speech waveform power exceeds the predetermined threshold value; and a step for recognizing the input speech using the set pronunciation information.