Provided is a camera self-calibration method that calculates a focal length of a fixed zoom lens camera from a correspondence point position between images. In the method, a cost function, which is a function of a focal length, is defined, and a focal length that minimizes the defined cost function is obtained to obtain a focal length that allows 3D recovery results of correspondence points calculated from all image pairs coincide with one another. Therefore, reliability of the calculated focal length can be easily verified, and the focal length of the camera can be stably calculated even when the position of input correspondence point is inaccurately given.