A communication method for transmitting information via a plurality of first communication stations (30-1, 30-2) to a second communication station, the communication method comprising: the second communication station receiving the information via one of the first communication stations; and when a function of the one of the first communication stations is transferred to another one of the first communication stations, the other one of the first communication stations receiving the information transferred from the one of the first communication stations and transferring the received information to the second communication station; characterized by: the other one of the first communication stations attaching order information to directly-transferred information to be transferred directly from the other one of the first communication stations to the second communication station, the order information being used by the second communication station to order the directly-transferred information and the information that is transferred from the one of the first communication stations via the other one of the first communication stations to the second communication station and includes information that has been transferred from the one of the first communication stations to the second communication station but for which acknowledgement has not been received, wherein the order information is a transmission serial number starting from an initial value that is obtained by adding a predetermined value to a used transmission serial number being used between the one of the first communication stations and the second communication station and that does not coincide with the used transmission serial number. the second communication station receiving the information via one of the first communication stations; and when a function of the one of the first communication stations is transferred to another one of the first communication stations, the other one of the first communication stations receiving the information transferred from the one of the first communication stations and transferring the received information to the second communication station; characterized by: the other one of the first communication stations attaching order information to directly-transferred information to be transferred directly from the other one of the first communication stations to the second communication station, the order information being used by the second communication station to order the directly-transferred information and the information that is transferred from the one of the first communication stations via the other one of the first communication stations to the second communication station and includes information that has been transferred from the one of the first communication stations to the second communication station but for which acknowledgement has not been received, wherein the order information is a transmission serial number starting from an initial value that is obtained by adding a predetermined value to a used transmission serial number being used between the one of the first communication stations and the second communication station and that does not coincide with the used transmission serial number.