PURPOSE: To accurately read an individual code despite its comparatively large error by irradiating the individual beams on each space of a unit and detecting individually these beams to read the individual code information by combination of beam detection information.

CONSTITUTION: A unit 5 of a mark sheet which is used for reading the individual code information is divided into four spaces 1-4. Some of spaces 1-4 are completely painted out and others are left blank as they are, and either one of decimal numeric characters 0-9 shown on the spaces 1-4 is specified by combination of painted-out spaces and blank spaces. When the code information on such mark sheets are read, the spaces 1-4 of each unit 5 are irradiated by the individual beams respectively. Then these irradiated beams are individually received and detected by a sensor for each space in response to the degree of transmission or reflection of those beams.