A moving picture encoding device that divides an encoding target picture into a plurality of target blocks, generates a prediction signal with reference to at least one reference picture of a plurality of reference pictures, and performs prediction encoding for every target block, the moving picture encoding device comprising: a prediction signal generation method controller that determines a processing method to be performed on the reference picture for generating the prediction signal on each of the plurality of reference pictures, the processing method determined by combining a predetermined plurality of processes, and the prediction signal generation method controller determines a motion vector and a reference picture on each target block by performing motion prediction for every processing block, wherein the prediction signal generation method controller is configured to determine a specific processing method as the processing method to be performed on the reference picture in such a manner that an error between a prediction signal obtained when processing is performed on the reference picture based on the specific processing method and the corresponding target block becomes minimum; a prediction signal generator that generates the prediction signal for the target block by performing processing on the reference picture, based on the processing method determined by the prediction signal generation method controller, the processing method to be performed on the reference picture for the target block; and an encoder that encodes information on the processing method on each reference picture determined by the prediction signal generation method controller together with a reference list number identifying a reference picture and motion vector information of every target block, wherein the processing method is pixel interpolation, and the predetermined plurality of processes includes accuracy of pixel interpolation, type of pixel interpolation filter, and calculation rounding method for pixel interpolation; and wherein the calculation rounding method indicates whether a fractional value during the calculation is to be rounded into an integer value only at the calculation end or during every calculation, during the calculation of filtering already reconstructed reference picture when a prediction signal with fractional pixel accuracy is produced, by pixel interpolation, from the already reconstructed reference picture. a prediction signal generation method controller that determines a processing method to be performed on the reference picture for generating the prediction signal on each of the plurality of reference pictures, the processing method determined by combining a predetermined plurality of processes, and the prediction signal generation method controller determines a motion vector and a reference picture on each target block by performing motion prediction for every processing block, wherein the prediction signal generation method controller is configured to determine a specific processing method as the processing method to be performed on the reference picture in such a manner that an error between a prediction signal obtained when processing is performed on the reference picture based on the specific processing method and the corresponding target block becomes minimum; a prediction signal generator that generates the prediction signal for the target block by performing processing on the reference picture, based on the processing method determined by the prediction signal generation method controller, the processing method to be performed on the reference picture for the target block; and an encoder that encodes information on the processing method on each reference picture determined by the prediction signal generation method controller together with a reference list number identifying a reference picture and motion vector information of every target block, wherein the processing method is pixel interpolation, and the predetermined plurality of processes includes accuracy of pixel interpolation, type of pixel interpolation filter, and calculation rounding method for pixel interpolation; and wherein the calculation rounding method indicates whether a fractional value during the calculation is to be rounded into an integer value only at the calculation end or during every calculation, during the calculation of filtering already reconstructed reference picture when a prediction signal with fractional pixel accuracy is produced, by pixel interpolation, from the already reconstructed reference picture.