Provided are a speckle-based authentication apparatus, an authentication system that includes the speckle-based authentication apparatus, and an authentication method using the speckle-based authentication apparatus. The speckle-based authentication apparatus includes an optical source configured to radiate light onto an object that is placed apart from the optical source; and a detector configured to detect a speckle pattern generated from the object in response to the light being radiated onto the object and detect location information of the object. Thus, the object is authenticated by comparing the speckle pattern detected by the detector with a speckle pattern stored in advance.