According to the present invention, when the block merge flag of the current prediction block specifies that the motion information of the current prediction block is acquired using block merging, the motion information of the current prediction block is acquired from the motion information of the neighboring block, a reference block of a reference picture is acquired using the motion information of the current prediction block, the prediction value of the current prediction block is acquired using the reference block, and the current prediction block is restored using the residual of the current prediction block and the prediction value of the current prediction block.