A wireless communication system comprising: a transmitter that has a manually operable switch wherein the transmitter is adapted to change, each time an ON operation of the switch in a predetermined first mode is performed, a frequency band among a plurality of predetermined frequency bands to transmit a wireless signal corresponding to the ON operation in the first mode, and to transmit, when an ON operation of the switch in a second mode that is different from the first mode is performed, a wireless signal corresponding to the ON operation in the second mode in one of the frequency bands, selected at that time; and a receiver that is adapted to receive the transmitted wireless signal and to recognize command information allocated in advance in correspondence with each of the ON operations of the switch in the respective modes, wherein the transmitter includes a frequency band computing unit that is adapted to select, when the ON operation of the switch in the second mode is repeatedly performed, one of the plurality of predetermined frequency bands through a computation for changing a communication environment, the number of the plurality of predetermined frequency bands is three or more, and the frequency band computing unit is adapted to learn as the computation for changing the communication environment, whether there is a successful communication of a wireless signal based on the ON operation of the switch in the first or second mode for each of the plurality of frequency bands and then to select the frequency band that is determined to have a high communication success rate through the learning as the frequency band when the ON operation of the switch in the second mode is repeatedly performed, the frequency band computing unit includes a storage device that is adapted to accumulatively store the number of successful communications of a wireless signal based on the ON operation of the switch in the first or second mode for each of the plurality of frequency bands, and the frequency band computing unit is adapted, as the learning, to obtain the frequency band having the largest number of successful communications accumulatively stored in the storage device and to select the obtained frequency band as the frequency band when the ON operation of the switch in the second mode is repeatedly performed. a transmitter that has a manually operable switch wherein the transmitter is adapted to change, each time an ON operation of the switch in a predetermined first mode is performed, a frequency band among a plurality of predetermined frequency bands to transmit a wireless signal corresponding to the ON operation in the first mode, and to transmit, when an ON operation of the switch in a second mode that is different from the first mode is performed, a wireless signal corresponding to the ON operation in the second mode in one of the frequency bands, selected at that time; and a receiver that is adapted to receive the transmitted wireless signal and to recognize command information allocated in advance in correspondence with each of the ON operations of the switch in the respective modes, wherein the transmitter includes a frequency band computing unit that is adapted to select, when the ON operation of the switch in the second mode is repeatedly performed, one of the plurality of predetermined frequency bands through a computation for changing a communication environment, the number of the plurality of predetermined frequency bands is three or more, and the frequency band computing unit is adapted to learn as the computation for changing the communication environment, whether there is a successful communication of a wireless signal based on the ON operation of the switch in the first or second mode for each of the plurality of frequency bands and then to select the frequency band that is determined to have a high communication success rate through the learning as the frequency band when the ON operation of the switch in the second mode is repeatedly performed, the frequency band computing unit includes a storage device that is adapted to accumulatively store the number of successful communications of a wireless signal based on the ON operation of the switch in the first or second mode for each of the plurality of frequency bands, and the frequency band computing unit is adapted, as the learning, to obtain the frequency band having the largest number of successful communications accumulatively stored in the storage device and to select the obtained frequency band as the frequency band when the ON operation of the switch in the second mode is repeatedly performed.