In a personal authentication medium issuing apparatus, a main image
information is input and whether a personal authentication medium on
which synthesized image information having sub-information embedded in
the main image information is checked or not is determined based on the
state of the input main image information. Further, synthesized image
information having sub-information embedded in an invisible state in the
main image information which is set in a visible state is formed, a
personal authentication medium is formed by printing the synthesized
image information on a recording medium and the thus formed personal
authentication media are sorted into personal authentication media
determined to be completely formed and personal authentication media
determined to require a checking process.