To make the delay times of a signal to be switched and a signal to be bypassed be the same or approximate as to signals of two systems or more in a signal transmission switching device.

A receiving means 21 receives a signal, a system distributing means 22 distributes the received signal to two systems or more, demodulating means 71 and 81 of the respective systems demodulate the distributed signals, switching and distributing means 91 and 92 input one branch signal obtained by branching the demodulated signals for two systems or more, switch a branch signal of one system and distributes the branch signal to two systems or more, delaying means 72 and 82 of the respective systems give a delay time being the same or approximate as to a delay time required for processing by the switching and distributing means to the other branch signal obtained by branching the demodulated signals, and switching and outputting means 93 and 94 of the respective systems switch and output one signal between the distributed signal of each system from the switching and distributing means and the delay signal of each system from the delay means of each system.