Abstract: An object is provision of a method and apparatus for generating ultrashort optical pulses through use of a Raman resonator, which can generate preferentially rotational Raman lines which resonate within the resonator, which can lower the threshold for generation of rotational Raman lines to thereby increase efficiency, and which enables generation of high-order rotational Raman lines to thereby obtain ultrashort optical pulses. An apparatus for generating ultrashort optical pulses by use of a Raman resonator includes a first laser (101); a second laser (102); a first wavemeter (111) for confirming the emitting wavelength of the first laser (101); a second wavemeter (121) for confirming the emitting wavelength of the second laser (102); and a Raman cell (130). These two laser beams are aligned by a beam splitter (113) to become coaxial and are focused by a lens (124) into the Raman cell (130).