PURPOSE: To read the data of an optional form mark sheet by reading the optically read and stored data of a mark sheet original and sending to the host computer, based upon position information of a data area read from the mark sheet format.

CONSTITUTION: A mark sheet format (MF) is optically read, converted to an electric signal by a one-directional image sensor 14, fetched through an I/O port 16 into a microcomputer, and written into a page memory 17 based upon the command of a CPU18. The CPU18 obtains a head address of a black block of MF and a length (l) in the (x) and (y) directions and stores them in a RAM19. When a mark sheet original reading button is pushed and the original is inserted into an inserting hole of OMR, reading is started and the read original is once stored in the memory 17. The head address and (l) are read from the RAM19, the memory 17 is accessed, the data of the original corresponding to a black block, and sent to a host computer.