Disclosed is a drop-and-continue device (84), provided between a signal converter (85) which supplies a signal to an end user and a wavelength-division multiplexing device (83) which comprises an optical demultiplexer (831) for separating an optical signal of a desired wavelength from an optical signal supplied from a head end station (82) and an optical multiplexer (832) for supplying an optical signal to a wavelength-division multiplexing device at a subsequent stage, comprising: an optical receiver (841) which converts the optical signal separated by the optical demultiplexer into an electrical signal; a transmitter (844) which transmits the electrical signal to the end user via the signal converter (85); an optical transmitter (845) which supplies an optical signal to the optical multiplexer (832); and a loopback processor (842) which loops the electrical signal output from the optical receiver back to the optical transmitter, thereby providing a drop-and-continue device that can easily add capabilities best suited for video, voice, and entertainment distribution and other added value features onto a WDM device.