PROBLEM TO BE SOLVED: To obtain an optical frequency COM in which the offset optical frequency is stabilized by enhancing the detection sensitivity of a CEO beat signal.SOLUTION: An optical frequency COM stabilization light source is constituted of a laser pulse light source 1, a non-linear medium 2 for enlarging the optical spectrum band of a laser pulse, wavelength 2 branch means 3 for branching broad spectrum band light into a long wavelength component and a short wavelength component, a non-linear optical crystal 4 for generating the second harmonic of long wavelength component of the broad spectrum band light, time difference adjustment means 5 for adjusting the optical path length of short wavelength component of the broad spectrum band light, 2 branch means 6 for branching the second harmonic of a long wavelength component and the short wavelength component into two after multiplexing, a balance receiver 7 for receiving the light branched into two and detecting a beat signal, and a feedback circuit 8 f
