To provide an improved and safe communication method in a data network by setting the different connection lines which are not dependent on the first communication path between the starting server and the terminating server while the first communication path is kept alive and transmitting the information via those set communication lines.

An information service offerer 101 is connected to an internet 102 via a digital transmission circuit 103. The internet 102 is accessed via a user terminal 104, and the terminal 104 is connected to the internet 102 via a modem and a subscriber line 105 of the telephone connected to a user regional communication network. Then a corporate web server 114 instructs a private branch exchange 120 to dial a telephone number designated by a circuit 123 that is not dependent on a digital transmission circuit 126 while the circuit 126 using a corporate data network 113 as the first communication path via the internet 102 and the server 114 is kept alive. Then a path is formed via communication carried out with the regional communication networks 106, 117 and 121 and an inter-office communication network 115 respectively.