An audio data processing device including: a first processor; and a second processor which is connected to the first processor wherein the first processor includes: an audio data acquisition which acquires audio data of digital data; an omitting section which omits a bit corresponding to low volume which is hard to be heard by human ears from the audio data; and a transmitter which transmits the audio data in which the bit corresponding to the low volume is omitted by the omitting section from the first processor to the second processor; wherein the second processor includes: a receiver which receives the audio data transmitted from the first processor; and a reproduction data generator which generates audio reproduction data necessary to reproduce the audio data based on the received audio data.