PURPOSE: To designate a field irrespective of the resolution of a reader by storing seal print field format information, and extracting an image correspond ing to the format information, when a cursor frame is displayed at a position containing a seal print field while bringing the cursor frame to a moving opera tion.

CONSTITUTION: When an account number is inputted, the corresponding reference seal print is read out of an optical disk 30, and stored in a memory in a display driving part 11. Subsequently, an application form is scanned by a reader 4, and the seal print is transferred to the memory and also displayed on a CRT10. Next the seal register format information and the seal print field format information are extracted by the moving operation of a cursor and stored in a memory 16. Thereafter, based on a coordinate and the size of a cursor frame, the seal print extraction in the cursor frame is executed by the first and the second seal print memories 22, 23, a seal shadow extraction control part 24, and an address control part 25. A reference seal print and the image of a collated seal print frame memory are superposed and displayed, and also the rate of polymerization and a density ratio are derived by an AND total bit calculating circuit at every same address.