To efficiently apply jitter to an optical signal using a simple configuration, provided is an optical signal output apparatus that outputs an optical pulse pattern signal including jitter, the optical signal generating apparatus comprising a light source section that outputs an optical signal having an optical frequency corresponding to a frequency control signal; an optical modulation section that modulates the optical signal output by the light source section, according to a designated pulse pattern; and an optical jitter generating section that delays an optical signal passed by the optical modulation section according to the optical frequency, to apply jitter to the optical signal.