To provide an optical wavelength tuning method by which a specific wavelength can be selected easily and highly efficiently, and an optical oscillator.

In a resonator 22, a titanium sapphire luminous medium 21 and an Nd:YAG optical absorber 23 are provided. The medium 21 is made to emit light by making 532 nm pumping light L2 generated by using an Nd: YAG laser 11 and a secondary higher harmonic generator 12 incident on the medium 21. The light emitted from the medium 21 has a continuous spectrum over a wide wavelength region of about 700-900 nm. The light is amplified by means of the resonator 22, and at the same time, selected according to the optical characteristics of the resonator 22 and the absorption spectrum of the Nd:YAG optical absorber 23. Consequently, oscillated light having high coherence of about 710 nm is outputted from the resonator 22.