The present invention is a carrier state judging device having a multiplexing unit multiplexing carrier signals to be inputted in parallel, output control units inputted to the multiplexing unit and performing ON/OFF control of outputs of the carrier signals inputted to the output control units themselves according to predetermined ON/OFF setting values, frequency shift units and giving predetermined frequency shift quantities to the carrier signals inputted to the frequency shift units themselves, a detection unit detecting as to whether or not there is the carrier signal flowing through on each carrier signal transmission path, and a determining unit determining a state of the carrier signals multiplexed by the multiplexing unit on the basis of the ON/OFF setting value with respect to each of the output control units, the frequency shift quantity with respect to each of the frequency shift units and a result of the detection by the detection unit.