According to one embodiment, a base station apparatus includes: a radio equipment control that generates a baseband signal including data; a microwave apparatus that modulates the baseband signal to a microwave to transmit by radio; a microwave apparatus that demodulates the received first microwave to the baseband signal, then extracts a clock from a cycle of the data included in the baseband signal, imports the baseband signal in synchronization with the clock, and plays back the data; and a radio equipment that modulates the data played back by the microwave apparatus to a high-frequency signal, and the microwave apparatus outputs dummy data instead of the played back data when a frequency fluctuation amount of the clock exceeds a predetermined range.