Optical encoder

Patent Pending PROBLEM TO BE SOLVED: To measure a displacement over a long range by using a connected scale while suppressing an error of displacement measurement caused by the enlargement of a sensor head and the inclination of a scale. ; SOLUTION: The sensor optical system 1 of the optical encoder includes: a single light source 10; a multi-probe generation mechanism 11; and a light receiving element unit 12 comprised of a plurality of light receiving elements 13, as a part of component, to measure displacement over long range by using a connecting scale 2.