Moving picture coding device and moving picture coding method

A moving picture coding method of coding a moving picture using motion compensation prediction in units of blocks acquired by dividing each picture of the moving picture, comprising:

• a motion information deriving step of deriving motion information from any of blocks spatially and blocks temporally neighboring a coding target block and storing the derived motion information without converting from bi-prediction into single prediction even if a prediction block size is smaller than a certain size;
• and
• a motion compensation predicting step of performing motion compensation prediction using the derived motion information if the prediction block size is larger than or equal to the certain size, and performing motion compensation prediction assuming the motion information as single prediction instead of using the derived motion information if the prediction block size is smaller than the certain size even when the derived motion information is bi-prediction.