An audio compression and decompression device of the present invention includes an LPF (102) which cuts off high frequency components existing at a high-frequency band of the digital audio data before compressed which are inputted to an ADPCM circuit (101) when the digital audio data are compressed or decompressed by the ADPCM method, thereby reducing quantization noises on the high-frequency band, occurring in the digital audio data after decompressed due to an increase of the compression ratio. The audio compression and decompression device further includes a controller (103) which can change characteristics of the LPF (102) according to a compression bit rate of the ADPCM circuit (101), thereby configuring the LPF so as to have optimum characteristics suited to the compression bit rate, and can reproduce the audio data in a sound quality that satisfies the user's preference.