5. The speech recognition apparatus according to claim 4 , further comprising: a retrieving device that defines a letter number, which is determined by a number of letters included in the correction character string, as a correction letter number, and retrieves all of character strings having the correction letter number in the correction range, wherein: the detection device detects one of the character strings retrieved by the retrieving device, which has a maximum number of letters that coincide with the correction character string, as the misrecognition character string.
5. The speech recognition apparatus according to claim 4 , further comprising: a retrieving device that defines a letter number, which is determined by a number of letters included in the correction character string, as a correction letter number, and retrieves all of character strings having the correction letter number in the correction range, wherein: the detection device detects one of the character strings retrieved by the retrieving device, which has a maximum number of letters that coincide with the correction character string, as the misrecognition character string. 9. The speech recognition apparatus according to claim 5 , wherein: the detection device detects one of the character strings in the correction range having a maximum number of letters that coincide with the correction character string, the input of which is received by the reception device, as the misrecognition character string; and the correction device executes the correction by replacing the misrecognition character string detected by the detection device with the correction character string relating to detection of the misrecognition character string; the apparatus further comprising: a memory device that stores the misrecognition character string relating to the correction executed by the correction device and the correction character string, with which the misrecognition character string is replaced, as a correction record, wherein: when the detection device detects a plurality of character strings in the speech character string as the misrecognition character string with respect to one correction character string, the detection device specifies a proper misrecognition character strings among a plurality of detected character strings based on the misrecognition character string relating to the correction record.