An apparatus for calculating optical flow and camera motion using correlation matching and a system model in a moving image, in which the calculation of the optical flow is executed accurately in real time, even when an image rotation or zoom change has occurred. The apparatus comprises a feature point extracting section for extracting a feature point of a sequence of input images (previous image and current image); an optical flow calculating section for calculating an optical flow by use of the feature point extracted by the feature point extracting section; a first camera motion calculating section for calculating a camera motion by use of the optical flow calculated by the optical flow calculating section; a second camera motion calculating section for eliminating an incorrect optical flow from the optical flow calculated by the optical flow calculating section and again calculating camera motion; an optical flow location estimating section for estimating a location of the optical flow by estimating a distance difference between an estimated feature point location and a current feature point location in the previous image according to the camera motion calculated by the second camera motion calculating section; and a weighted value calculating section for calculating a weighted value according to the camera motion calculated by the second camera motion calculating section and providing the weighted value to the optical flow calculating section.