Face authentication system and face authentication method

A face authentication system that registers a face image of a user in a facility and performs face authentication for each event generated due to an action of the user in the facility, the face authentication system comprising:

• a processor that is in the facility and acquires a first face image for registration of the user and specific information different than the first face image, the specific information being used for specifying the user;
• a plurality of cameras, including at least one camera that acquires a second face image for authentication of the user, the second face image being captured when the event is generated;
• a face management server that is connected to the processor via a network and stores the first face image of the user for registration in association with the specific information in accordance with a collation group set for the user from among a plurality of collation groups;
• and
• a plurality of face collation servers configured to generate face feature data from the first face image for registration and the second face image for authentication, and perform collation processing between pieces of the face feature data,
• wherein each of the plurality of collation groups is associated with one of the plurality of face collation servers,
• the first face image of the user is stored in association with the specific information in the one of the plurality of face collation servers which is associated with the collation group set for the user, and
• each of the plurality of cameras is associated with at least one of the plurality of collation groups and performs the authentication of the user in accordance with the plurality of face collation servers which are associated with the at least one of the plurality of collation groups.