An optical time-division multiplex signal processing apparatus includes an optical dispersion part providing optical dispersion to an optical time-division multiplex signal and an optical clock signal, an optical detector coupled optically to the optical dispersion part for detecting a beat signal formed between the optical time-division multiplex signal and the clock signal in a superposed state, and a filter connected to an output terminal of the optical detector for filtering out an electric signal of a desired frequency band from an output electric signal of said optical detector.