Optical information reproduction device and optical information reproduction method

An optical information reproduction device which reproduces information from an optical information storage medium by using holography, comprising:

• a laser light source for generating a reference beam;
• an image-capturing unit for detecting a diffracted beam to be reproduced from the optical information storage medium;
• an optical detection unit having at least two light-receiving surfaces and used for detecting a diffracted beam reproduced by irradiating the optical information storage medium with the reference beam;
• a light-shielding unit for shielding a part of the diffracted beam detected by the optical detection unit;
• and
• an error signal calculation unit for generating an angle error signal from a detection signal outputted by the optical detection unit,
• wherein the light-shielding part is disposed at a position other than a focal point of the diffracted beam, and shields at least one end in a multiplexing direction of the diffracted beam detected by the optical detection unit or in a direction perpendicular to the multiplexing direction,
• wherein the optical detection unit outputs different detection signals with respect to reference beams having different angles, and
• wherein the angle error signal calculation unit generates the angle error signal of the reference beam based on the a differential operation signal of at least two detection signals output from the optical detection unit.