A radio-frequency communication device arranged to transmit a transmitted signal from a transmitter antenna device toward a communication object, and to receive through a receiver antenna device a reply signal transmitted from the communication object, for radio communication with the communication object, the radio-frequency communication device including a transfer-function calculating portion operable to calculate a transfer function indicative of a relationship between a signal input to the transmitter antenna device and a signal generated by the receiver antenna device due to the signal input to the transmitter antenna device, and a receiver-circuit-constant setting portion operable to set a receiver-circuit constant for improving a quality of the reply signal received by the receiver antenna device, on the basis of the transfer function calculated by the transfer-function calculating portion, and the signal input to the transmitter antenna device.