Provided are a base station and a wireless communication method with which it is possible to avoid the effect of interference affecting another wireless communication system in a common band of wireless communication, and to provide high-speed communication service. The present invention has a configuration provided with a base station (30x) in which, when the other wireless communication system is not using the common band, a 3 MHz or 5 MHz carrier of the host system is used in which throughput is improved in comparison to a carrier having the frequency width of the other wireless communication system, and when the other wireless communication system is using the common band, a 1.4 MHz carrier of the host system is used having a smaller frequency width than the other wireless communication system.