To provide a storage medium for storing authentication information capable of improving accuracy of authentication which has high image quality, an authentication card, an authentication method, an authentication device and an authentication system.

A storage medium 61 stores authentication information including image data and accompanying data and can be read by an authentication device 6 for authenticating an object based on the authentication information. The image data includes main part data structured by compression processing for compressing an area including the main part of an original image data of the object for authentication as a minimum data compression unit.