An electronic image data verification program disclosed herein is capable of detecting presence or absence of a change, specifying a changed portion (the position of a change) if present, and making the presence or absence and the changed portion provable to third parties, by generating partial signature information separately from electronic image information to be registered, by dividing and maintaining the partial signature information, and by clearly separating functions/roles of the electronic image information (original information) and the partial signature information (verification information). The present invention comprises: a partial signature information generation section 40 that uses partial information of electronic image information, to generate partial signature information for specifying presence or absence of a change to the electronic image information and a changed portion if a change has been made; a registration section 70 that registers the electronic image information and the partial signature information generated from the electronic image information; a storage section 80; and a partial signature verification section 50 that uses the electronic image information and the partial signature information registered by the registration section, to verify presence or absence of the change to the electronic image information, or a changed portion if a change has been made to the electronic image information.