A motion detection portion of a video encoding apparatus conducts motion detection on each of frame macroblocks and field macroblocks to calculate motion vectors and respective detection cost. A motion vector evaluation value calculation portion calculates an evaluation value of the size of motion vectors. A motion vector threshold determination portion compares the evaluation value of the size of motion vectors to a predetermined threshold to determine whether the target area is a moving area or a still area. If the target area is a moving area, it is determined whether frame or field macroblock mode is to be used by comparing the detection costs. If the target area is a still area, it is determined whether frame or field macroblock mode is to be used in accordance with the size of the sum of absolute values of differences between neighboring pixels in a vertical direction regarding the frame macroblock and field macroblock.