A face feature value vector extracting section extracts a feature value from a registered image of a registrant to generate a face feature value vector. A virtual face feature value vector generating section converts the face feature value vector using a feature value converter which performs a conversion in a feature value space. Then, a registration information generating section generates face definition information of the registrant based on a face feature value vector before conversion and a virtual face feature value vector after conversion and registers this information in a registration information storing section.