1. A moving picture prediction method for predicting pixel values in a picture that forms a moving picture based on pixel values in two reference pictures, the method comprising: a first parameter calculation step of calculating a first parameter corresponding to a distance between a current picture and a first reference picture; a second parameter calculation step of calculating a second parameter corresponding to a distance between the first reference picture and a second reference picture; a first judgment step of judging whether a third parameter calculated based on the first and the second parameters is included in a predetermined range or not; a first prediction step of calculating pixel values in the current picture by scaling based on the first and the second parameters and pixel values in the first and the second reference pictures when a result of the judgment in the first judgment step shows that the third parameter is included in the predetermined range; and a second prediction step of calculating pixel values in the current picture by scaling based on predetermined values and pixel values in the first and the second reference pictures when a result of the judgment in the first judgment step shows that the third parameter is not included in the predetermined range.