Optical disc device and spherical aberration error signal detection method

An optical disc device that performs recording on lands and grooves of an optical disc, the optical disc device comprising:

• an optical path splitter configured to split a luminous flux returning from the optical disc into a first optical path and a second optical path;
• a first detector configured to receive a whole of the luminous flux that has passed through the first optical path;
• a second detector configured to receive a luminous flux of an inside part of the luminous flux that has passed through the second optical path;
• a spherical aberration error signal generation unit configured to generate a spherical aberration error signal on the basis of a difference between a first focus error signal obtained on the basis of a detection signal of the first detector and a second focus error signal obtained on the basis of a detection signal of the second detector;
• a spherical aberration correction unit configured to correct spherical aberration upon receipt of the spherical aberration error signal;
• and
• an adjustment unit configured to adjust the spherical aberration error signal,
• wherein the adjustment unit adjusts a servo gain value of the spherical aberration error signal and a convergence value of the spherical aberration error signal to optimal values for each land and each groove.