A peeling sheet on the back of a cover sheet is provided with a cover seal having a printed front surface is peeled off to partially expose an adhesive layer. A core material for cover is placed thereon. First side piece portion and second side piece portion are then peeled off and the entire surface of the first cover members, backbone member and second cover member of the core material for cover is bonded and fixed by the adhesive layer of the cover sheet for cover. Outer circumferential region of the cover seal for cover is then bent to the inside thus making a cover of a booklet. When a personal user edits electronic images and prints the electronic images on a printed sheet, the printed sheet can be fixed easily in a short time for making a booklet.