A speech recognition method comprising: determining a criteria value to determine a length of a silent section included in a processing section, corresponding to an utterance and including also a sound section at a head of the processing section, the silent section immediately following the sound section to the end of the processing section; determining whether the length of the silent section is longer than the criteria value, or not; determining a processing mode out of multiple processing modes for audio processing of which processing amounts differ from each other, the multiple processing modes including (i) a first processing mode which has a high processing amount and a high performance processing and (ii) a second processing mode which has a low processing amount and a low performance processing, wherein when the length of the silence section is determined to be longer than the criteria value, the processing mode is determined to be the first processing mode, and when the length of the silence section is determined not to be longer than the criteria value, the processing mode is determined to be the second processing mode; obtaining audio information in the processing section including a section of interest being the sound section, out of audio information in an input section including the processing section, using the criteria value; executing audio processing on the audio information in the section of interest, out of the audio information in the processing section, using the processing mode that has been determined; executing speech recognition processing on the audio information in the section of the interest where the audio processing has been performed, wherein the audio processing is noise suppression processing of the audio information, and wherein, in the determining of the processing mode, a noise suppression algorithm or a noise suppression parameter is determined as the processing mode. determining a criteria value to determine a length of a silent section included in a processing section, corresponding to an utterance and including also a sound section at a head of the processing section, the silent section immediately following the sound section to the end of the processing section; determining whether the length of the silent section is longer than the criteria value, or not; determining a processing mode out of multiple processing modes for audio processing of which processing amounts differ from each other, the multiple processing modes including (i) a first processing mode which has a high processing amount and a high performance processing and (ii) a second processing mode which has a low processing amount and a low performance processing, wherein when the length of the silence section is determined to be longer than the criteria value, the processing mode is determined to be the first processing mode, and when the length of the silence section is determined not to be longer than the criteria value, the processing mode is determined to be the second processing mode; obtaining audio information in the processing section including a section of interest being the sound section, out of audio information in an input section including the processing section, using the criteria value; executing audio processing on the audio information in the section of interest, out of the audio information in the processing section, using the processing mode that has been determined; executing speech recognition processing on the audio information in the section of the interest where the audio processing has been performed, wherein the audio processing is noise suppression processing of the audio information, and wherein, in the determining of the processing mode, a noise suppression algorithm or a noise suppression parameter is determined as the processing mode.