PURPOSE: To provide a synchronization network radio transmitting system where synchronization switching is realized at a reception side by following the switching at the transmission side even if an active line signal is switched into a stand-by line signal at the transmission side.

CONSTITUTION: The plural active lines and the one stand-by line are switched without instantaneous disconnection in the synchronization network radio transmitting system which is provided with a synchronization network clock/frame pulse supplying part 2 distributing a synchronization network clock which keeps the operation timing of a synchronization network to the stand-by system and the respective active systems together with a frame timing, an active line signal switching part 3 outputting the respective active line signals which are changed onto the supplied clock and frame timing to a stand-by line transmission end switching part 5 and a stand-by line clock changing memory part 6 which stores the switched signal and also reads out it through the use of the syncronization network clock and frame timing so as to transmission-output it as the stand-by line signal.