A communication control method for double ring networks including a set of two or more transmission stations (#ST1-#ST8) each respectively configured with a pair of communication ports for communications to be implemented bi-directionally, and mutually connected by said pairs of communication ports thereof in a ring form through a transmission line to implement intercommunications between transmission stations, characterized for the respective transmission station, by: a step of simultaneously sending transmission frames containing information at a time from paired communication ports of said transmission station; a step of detecting a transmission frame sent from another said transmission station received at one of said paired communication ports; and a step of sending above-noted said transmission frame as repeatable to another communication port being the other with respect to the one communication port, from said other communication port, and for a respective one of adjacent paired said transmission stations out of said set of two or more transmission stations mutually connected in the ring form in positions determined relative to one said transmission station as a base in accordance with a total number of said transmission stations constituting the network of the ring form and a total length of the transmission line connecting said transmission stations with each other, by: a step of having the transmission frame sent from one said transmission station's communication port; and a step of performing, for a transmission frame received at the other said transmission station's communication port as it is connected through the transmission line, a detection at this station, and in that said transmission frame to be responded in accordance with information contained in said transmission frame is kept from being sent, through a repeating from said receiving communication port to the other communication port, from said other communication port, whereby said received transmission frame is kept from arriving at ring-form connected and subsequent transmission stations in a repeating direction thereof, and above-noted transmission frames sent from said transmission station are kept from circulating in a network configured in the ring form. a step of simultaneously sending transmission frames containing information at a time from paired communication ports of said transmission station; a step of detecting a transmission frame sent from another said transmission station received at one of said paired communication ports; and a step of sending above-noted said transmission frame as repeatable to another communication port being the other with respect to the one communication port, from said other communication port, and for a respective one of adjacent paired said transmission stations out of said set of two or more transmission stations mutually connected in the ring form in positions determined relative to one said transmission station as a base in accordance with a total number of said transmission stations constituting the network of the ring form and a total length of the transmission line connecting said transmission stations with each other, by: a step of having the transmission frame sent from one said transmission station's communication port; and a step of performing, for a transmission frame received at the other said transmission station's communication port as it is connected through the transmission line, a detection at this station, and in that said transmission frame to be responded in accordance with information contained in said transmission frame is kept from being sent, through a repeating from said receiving communication port to the other communication port, from said other communication port, whereby said received transmission frame is kept from arriving at ring-form connected and subsequent transmission stations in a repeating direction thereof, and above-noted transmission frames sent from said transmission station are kept from circulating in a network configured in the ring form. a step of having the transmission frame sent from one said transmission station's communication port; and a step of performing, for a transmission frame received at the other said transmission station's communication port as it is connected through the transmission line, a detection at this station, and in that said transmission frame to be responded in accordance with information contained in said transmission frame is kept from being sent, through a repeating from said receiving communication port to the other communication port, from said other communication port, whereby said received transmission frame is kept from arriving at ring-form connected and subsequent transmission stations in a repeating direction thereof, and above-noted transmission frames sent from said transmission station are kept from circulating in a network configured in the ring form.