A temporal merging motion information candidate generation unit derives, when information indicating whether or not to derive a temporal merging motion information candidate shared for all prediction blocks in a coding block is information indicating the derivation of a temporal merging motion information candidate shared for all the prediction blocks in the coding block, a temporal merging motion information candidate shared for all the prediction blocks in the coding block from a prediction block of a coded picture different from a picture having a prediction block subject to coding. A merging motion information candidate list construction unit generates a plurality of merging motion information candidates including a temporal merging motion information candidate.