A wireless communication apparatus includes a DC/DC converter that is operated based on a second clock signal generated by an oscillator with high accuracy when receiving the annunciation signal. Therefore, it is possible to reduce negative influences on other electrical apparatuses due to the conduction noise. The DC/DC converter is operated based on first clock signal generated by an oscillator with low accuracy while in a non-receiving time of the annunciation signal. Therefore, it is possible to reduce negative influence on other electrical apparatuses and to reduce the consumption of electrical power.