A signal converting apparatus with a relay function connector includes a body, a signal converting unit installed in the body and having a signal connecting portion connected to an electronic device for transmitting or receiving a first signal, and at least one first signal line is extended into the body and connected to the signal converting unit. The signal connecting portion is connected to another signal converting apparatus through the first signal line, and a relay function wire terminal is installed in the body and has an end connected to a second signal line. The second signal line is connected to the electronic device or an electric equipment for transmitting/receiving a second signal to/from the electronic device or electric equipment respectively. The relay function wire terminal is connected to a third signal line, and the third signal line is connected to an electric adapter of another signal converting apparatus.