An audio processing device includes an acquisition unit that acquires audio that is picked up by a sound pick-up unit, a detector that detects an audio position of the audio, a determiner that determines whether or not the audio is a speech audio when the audio position is within a privacy protection area, an analyzer that analyzes the speech audio to acquire an emotion value, a converter that converts the speech audio into a substitute sound corresponding to the emotion value, and an output controller that causes an audio output that outputs the audio to output the substitute sound.