1. A moving picture encoding apparatus for dividing a frame image as an encoding target in a moving picture signal including a temporal series of frame image signals, into a plurality of target regions, detecting motion vectors for the respective target regions with reference to a plurality of frame images different from the frame image as the encoding target, and thereby performing encoding based on motion compensation, the moving picture encoding apparatus comprising: circuitry configured to select one predicted motion vector from among motion vectors of adjacent regions adjacent to a target region; determine whether the selected predicted motion vector meets predetermined criteria including a criterion that the selected predicted motion vector corresponds to a same reference frame image as a target reference frame image referred by the motion vector of the target region in the motion compensation process; and after selecting the one predicted motion vector, correct a scale of the selected predicted motion vector based on the target reference frame image when the selected predicted motion vector does not meet the criteria based on a temporal relation among an adjacent reference frame image referred for detecting a motion vector of the adjacent region, the target reference frame image, and a target frame image being the frame image as the encoding target, or based on time information thereof, wherein at least two of the adjacent regions adjacent to the target region refer respectively to two different reference frame images for detecting the motion vectors of the adjacent regions, wherein when selecting the predicted motion vector, the predicted motion vector is selected without performing the scaling on the basis of the target reference frame image, wherein when correcting the scale of the selected predicted motion vector, the length of the x or y component of the selected motion vector is scaled so as to meet the same reference frame condition for the target region, and when the selected predicted motion vector meets the criteria, the x component or the y component of the selected predicted motion vector is determined to be the predicted motion vector as it is.