A communication device according to an embodiment includes: a processor configured to execute a media clock for generating a frame synchronization signal having a frequency which is m times a sampling frequency; a first interface configured to output 2m-channel audio data to a DAC or receive an input of the 2m-channel audio data from an ADC, in synchronization with the frame synchronization signal; and an external counter configured to generate a frequency-divided frame synchronization signal obtained by 1/m-frequency division of the frame synchronization signal and output the frequency-divided frame synchronization signal to the DAC and the ADC.