A digital recording device includes a microphone configured to convert collected sound into an analog audio signal; a first analog to digital converter configured to convert the signal converted by the microphone into a digital audio signal; a first memory configured to store the digital audio signal of the first analog to digital converter; an attenuator configured to attenuate the analog audio signal with a predetermined attenuation factor; a second analog to digital converter configured to convert the attenuated signal into a digital audio signal; a second memory configured to store the digital audio signal of the second analog to digital converter; an audio signal generating unit configured to extract the digital audio signal in one of the first memory and the second memory for a required time range according to an amplitude maximum value of the signal, and generate a new digital audio signal; and an audio signal memory for storing the generated digital audio signal.