Abstract: An apparatus for estimating real-time motion in a motion compensated predicative coder for data compression of a motion image includes a previous block formation unit, a block-matching algorithm detector, minimum absolute error detecting means, a motion vector generator, and an output controller. Also, a suitable real-time motion estimating method is provided. In the present invention, to minimize the number of I/O pins, serial input system is utilized for data input from an external portion, all previous blocks and current blocks are simultaneously processed in parallel by means of a pipeline system in internal processing, and a minimum value for each group is detected together with the selection of a corresponding motion vector. As a result, a high processing speed can be achieved which enables the estimation of real-time motion.