An optical information processing apparatus includes: an optical head for irradiating an optical information recording medium with light, converting the light reflected by the optical information recording medium into a head signal and outputting the head signal; a signal quality index detector for detecting a signal quality index representing quality of the head signal on the basis of the head signal; and a two-dimensional probe for varying the focal position and the spherical aberration of the light radiated onto the optical information recording medium so as to search for a focal position and a spherical aberration that optimize the signal quality index detected by the signal quality index detector.