According to one embodiment, transmission circuitry transmits power with a first electromagnetic wave in a first frequency band. A processor circuitry executes a carrier sense during a first period, in at least a second frequency band different from the first frequency band. The transmission circuitry transmits power with a second electromagnetic wave in the first frequency band in a second period following the first period, if a wireless signal is not detected by the carrier sense during the first period. The processor circuitry executes the carrier sense during a third period following the first period in the at least the second frequency band, if the wireless signal is detected by the carrier sense during the first period.