An audio output device according to an embodiment may include: a short-range communication module configured to perform short-range wireless communication; a memory configured to buffer audio data received from an external electronic device through the short-range communication module; an audio output unit configured to output the audio data; and a processor. The processor may be configured to: receive operation mode information related to a function being executed in the external electronic device from the external electronic device through the short-range communication module; configure a reference period corresponding to an amount of the audio data buffered in the memory based on the operation mode information; and determine a playback speed of the audio data to be output through the audio output unit by comparing the amount of the buffered audio data with the configured reference period. In addition, various other embodiments may be possible.