A motion estimation apparatus for moving picture coding comprising: a 1-pel buffer for storing the luminance values of 1-pel unit pixels of a reference frame which correspond to a search window for a macroblock of a current frame; a 1-pel estimator adapted to calculating 1-pel unit motion vectors and minimum costs in correspondence to the macroblocks of the current frame and the pixels stored in the 1-pel buffer; a 1/2-pel interpolator adapted to performing 1/2-pel unit interpolation using the pixels stored in the 1-pel buffer; a 1/2-pel buffer adapted to storing the 1/2-pel unit interpolated pixels; a 1/2-pel estimator adapted to calculating 1/2-pel unit motion vectors and minimum costs by calculating the minimum block distortion in form of the sum of the absolute differences and the corresponding motion vector in correspondence to the pixels stored in the 1/2-pel buffer, the values calculated by the 1-pel estimator, and the macroblocks of the current frame; a 1/4-pel interpolator adapted to performing 1/4-pel unit interpolation using the pixels stored in the 1/2-pel and 1-pel buffers; a 1/4-pel buffer adapted to storing the 1/4-pel unit interpolated pixels; and a 1/4-pel estimator adapted to calculating 1/4-pel unit motion vectors and minimum costs by calculating the minimum block distortion in form of the sum of the absolute differences and the corresponding motion vector in correspondence to the pixels stored in the 1/4-pel buffer, the values calculated by the 1/2-pel estimator, and the macroblocks of the current frame, wherein the 1/2-pel buffer includes physically separated three memories, and stores the 1/2-pel unit interpolated pixels interpolated from the pixels included in the 1-pel buffer in correspondence to the motion vectors determined by the 1-pel estimator, wherein the 1/4-pel buffer includes physically separated eight memories which store 16x16 pixels, respectively, and stores 1/4-pel unit interpolated pixels interpolated from the pixels included in the 1/2-pel buffer in correspondence to the motion vectors determined by the 1/2-pel estimator, wherein the 1/4-pel unit interpolated pixels are located inside a search window at 1-pel unit intervals at offsets according to the eight contour pixels of a 3x3 block with reference to pixels inside the search window at which the motion vectors determined by the 1/2-pel estimator point, characterized in that the 1/4-pel estimator calculates 1/4-pel unit costs of pixels stored in each of the eight memories of the 1/4-pel buffer at the same time. a 1-pel buffer for storing the luminance values of 1-pel unit pixels of a reference frame which correspond to a search window for a macroblock of a current frame; a 1-pel estimator adapted to calculating 1-pel unit motion vectors and minimum costs in correspondence to the macroblocks of the current frame and the pixels stored in the 1-pel buffer; a 1/2-pel interpolator adapted to performing 1/2-pel unit interpolation using the pixels stored in the 1-pel buffer; a 1/2-pel buffer adapted to storing the 1/2-pel unit interpolated pixels; a 1/2-pel estimator adapted to calculating 1/2-pel unit motion vectors and minimum costs by calculating the minimum block distortion in form of the sum of the absolute differences and the corresponding motion vector in correspondence to the pixels stored in the 1/2-pel buffer, the values calculated by the 1-pel estimator, and the macroblocks of the current frame; a 1/4-pel interpolator adapted to performing 1/4-pel unit interpolation using the pixels stored in the 1/2-pel and 1-pel buffers; a 1/4-pel buffer adapted to storing the 1/4-pel unit interpolated pixels; and a 1/4-pel estimator adapted to calculating 1/4-pel unit motion vectors and minimum costs by calculating the minimum block distortion in form of the sum of the absolute differences and the corresponding motion vector in correspondence to the pixels stored in the 1/4-pel buffer, the values calculated by the 1/2-pel estimator, and the macroblocks of the current frame, wherein the 1/2-pel buffer includes physically separated three memories, and stores the 1/2-pel unit interpolated pixels interpolated from the pixels included in the 1-pel buffer in correspondence to the motion vectors determined by the 1-pel estimator, wherein the 1/4-pel buffer includes physically separated eight memories which store 16x16 pixels, respectively, and stores 1/4-pel unit interpolated pixels interpolated from the pixels included in the 1/2-pel buffer in correspondence to the motion vectors determined by the 1/2-pel estimator, wherein the 1/4-pel unit interpolated pixels are located inside a search window at 1-pel unit intervals at offsets according to the eight contour pixels of a 3x3 block with reference to pixels inside the search window at which the motion vectors determined by the 1/2-pel estimator point, characterized in that the 1/4-pel estimator calculates 1/4-pel unit costs of pixels stored in each of the eight memories of the 1/4-pel buffer at the same time.