11. A speech correction apparatus comprising: a speaker for generating speech to be corrected; a microphone set at a hearing position; a signal separating unit for separating ambient noise from the speech to be corrected at the hearing position; a speech correcting unit for correcting a sound pressure level of the speech to be corrected generated by from the speaker based on an average power of the speech to be corrected and an average power of the ambient noise, which are separated by the signal separating unit; and a speech-head correcting unit for stopping correction of the sound pressure level which is performed by the speech correcting unit in accordance with a speech-head at the border between a silent state and a speech state in the speech to be corrected, wherein the correction of the sound pressure level is stopped based on a comparison between a time length Ls for calculating the average power of the speech to be corrected and a time length Ln for calculating the average power of the ambient noise.
12. A speech correction apparatus according to claim 11 , wherein the time length Ls for calculating the average power of the speech to be corrected is longer than the time length Ln for calculating the average power of the ambient noise.