An electronic device includes a processor. The processor is configured to examine the sound level of an audio signal obtained from an external object for a preset time; change, if the frequency with which the sound level becomes higher than or equal to a specified level satisfies a preset condition, a reference level, at which the gain value for audio signal amplification is changed in accordance with the amplitude change of the audio signal, for at least one section of the audio signal satisfying the preset condition; and amplify the at least one section of the audio signal according to the changed reference level.