A speech recognition apparatus recognizes a speech signal received from a speaker and provides the result of recognition for an external device. In the apparatus, a pattern matching section performs pattern matching between each of reference patterns in a vocabulary and characteristic parameters extracted from the speech signal. The vocabulary includes reference patterns corresponding to words. Further the apparatus has a similar sound group which includes reference patterns corresponding to the sound similar to that of a specific word. The specific word is a word in response to which the external device performs an operation which cannot be easily undone. The speech signal is rerecognized by using the similar sound group. As a result, the pattern matching section outputs a word other than the specific word, if one of the reference patterns in the similar sound group has a high similarity with the characteristic parameters.