An X-ray imaging system includes an X-ray imaging apparatus and an access controller, which controls communication access of the X-ray imaging apparatus having an electronic cassette for forming an X-ray image and wirelessly transmitting the X-ray image. Before the electronic cassette starts transmitting the X-ray image, a priority request signal for priority of the first radio communication channel to the electronic cassette over a portable terminal device of radio communication is received. Upon receiving the priority request signal, presence of the portable terminal device is checked, in which a radio communication channel of overlap of frequency on the first radio communication channel is used. In presence of the portable terminal device with the overlap, the portable terminal device is regulated in communication regulation while the electronic cassette transmits the X-ray image. Also, the X-ray imaging apparatus is communicable by use of a communication network in wireless communication connection.
