There is provided an image encoding apparatus that divides an image in a video into blocks made up of a plurality of pixels, and encodes the blocks, the image encoding apparatus comprising: A first motion vector computation unit configured to compute a first motion vector of a block to be encoded in an image to be encoded; A motion vector modification unit configured to modify the first motion vector computed in the first motion vector computation unit to generate a second motion vector when a first condition is satisfied; Wherein the first condition is at least one of the following conditions: The absolute value of the first motion vector is greater than a first threshold The absolute value of the difference between the first motion vector and the candidate motion vector for modifying the first motion vector is greater than a second threshold.