An optical pulse evaluation device and an in-service optical pulse evaluation device is disclosed which are capable of characteristics evaluation of an optical pulse itself or a sample launched therein in a relatively high bit-rate region. The optical pulse evaluation device evaluates a pulse waveform expressing an optical intensity of the optical pulse, an instantaneous frequency of the optical pulse, or a modulated light prepared by modulating the optical pulse in a light source end. The optical pulse evaluation device also observes a waveform change after a known optical pulse is passed through a device such as an optical fiber to evaluate a waveform deterioration or a compensation behavior caused by the device. The in-service optical pulse evaluation device is capable of measuring a wavelength dispersion in an optical communication.