An image encoding method configuring block division information and size information of a boundary block which is located at a boundary of an image and is smaller than a size of a basic encoding block, on the basis of size information of a picture and size information of the basic encoding block; dividing the boundary block into at least one encoding block, on the basis of the size information of the basic encoding block and the size information and the block division information of the boundary block; and encoding the at least one divided encoding block.