1. A face identification device comprising: a storing unit capable of storing face definition information which defines a face of a registrant; an identifying unit which performs face identification of a target to be identified by comparing a feature value extracted from a face image of the target to be identified with the face definition information stored in the storing unit; and a registering unit which generates the face definition information of the registrant and registers the face definition information of the registrant in the storing unit, wherein the registering unit includes: a feature value extracting unit which extracts the feature value from a face image of the registrant; a feature value converting unit which converts a vector of the extracted feature value using a converter which performs coordinate conversion in a feature value space; and a face definition information generating unit which generates the face definition information of the registrant based on the extracted feature value and a feature value including the vector after conversion, wherein the feature value converting unit is for converting a vector of a feature value obtained from a face image of the registrant captured under a first condition to a vector of a feature value obtained from a face image of the registrant captured under a second condition that is different from the first condition.