A control device includes a power detector that detects a power of a signal transmitted by an antenna, a transmitting power of the signal fluctuating due to transmit power control; and a controller that adjusts a setting value of a variable matching circuit in such a way that the power increases based on a result of comparison of a reference value with a detected power of the power detector, that detects fluctuation in the transmitting power based on a temporal change in the detected power, and that corrects the reference value based on the fluctuation in the transmitting power.