A further secure channel is ensured after switching of a modulation system at the time of deterioration channel quality. A wireless communication device includes a transmitter that converts data into a modulation wave in a set modulation system and transmits the modulation wave, a receiver that receives a transmitted modulation wave, and converts the modulation wave into original data based on a set modulation system, a determining means for determining quality of a channel on the basis of a signal received by the receiver, and a modulation system switching means for switching the modulation system to a modulation system that is strongest against external disturbance among a plurality of different modulation systems set in advance and then switching the modulation system to a modulation system in accordance with quality of the channel, when the determining means determines that quality of the channel is deteriorated.