Abstract: The voice detecting device includes a voice frequency detector for detecting the frequency of the input voice, then discriminating whether the detected frequency falls within a preset frequency range of voices to be detected, and outputting the result of the discrimination; an input signal level detector for detecting the energy level of the input voice, then comparing it to confirm whether the detected energy level exceeds a preset energy level threshold value of voices to be detected, and outputting the result of the comparison; a voice input judge part responsive to the result of discrimination and the result of comparison to judge whether a voice satisfying conditions for voice detection has been input or not, and output a first status signal in accordance with the result of the judgement; and a voice duration measure part for measuring the duration of the first status signal, then comparing it to confirm whether the detected duration falls within a preset range of duration threshold value, and outputting