The occurrence of interference is suppressed to improve the quality of radio transmission. A radio station (1r) performs the communication of a radio signal (d1). A radio station (2r) receives a radio signal (d2) which cannot be discriminated from the radio signal (d1). A radio station (3r) is located in the radio communication range of the radio station (1r) and in the service area of the radio station (2r). A communication method converting section (21) generates a radio signal (d2a) which is obtained by converting the communication method of the radio signal (d2) into a communication method which can be discriminated from the radio signal (d1) to perform communication with the radio station (3r) by the radio signal (d2a).