To establish network synchronism all over the network equipment by selecting a clock extracting route without interposing an operation maintenance person when a fault occurs in the route a master network synchronizing device concerning the network equipment composed of the master network synchronizing device and a slave network synchronizing device.

The master network synchronizing device sends repeating step number information, the slave network synchronizing device receives this repeating step number information from the adjacent network synchronizing device, the minimum number of repeating steps between the present device and the master network synchronizing device is determined on the basis of this repeating step number information, this minimum number of repeating steps is sent out as repeating step number information, and clock is extracted from the route, which receives the minimum number of repeating steps. Besides, each of network synchronizing device is provided with the second master network synchronizing device in addition to the first master network synchronizing device and when a device error occurs in the first master network synchronizing device, the second master network synchronizing device, which detects this device fault, performs the operation of network synchronizing master is place of the first master network synchronizing device.