To provide a strong impact of impression by applying the constitution that three-dimensional forming pieces are alternately jointed to each other, including a bottom folded joint part and a top folded joint part not kept in parallel to the joint part of a cardboard pair, and form a twisted plane when opened.

Cardboard pieces 2 and 2 are jointed to each other at a first joint part 3, and a three-dimensional forming piece 6 is formed to have a three dimensional forming part 8 having bottom and top joints parts 5 and 4, thereby forming a booklet 1. In addition, the three-dimensional forming part 8 have both ends pasted to the cardboard pieces 2 at a pasting part 7, across the first joint part 3. The bottom folded joint part 5 and the top folded joint part 4 are formed to include a segment not in parallel to the first joint part 3. In this case, all may not be kept in parallel or a parallel segment may be partly included. Also, an arbitrary image, character, background or the like is preferably printed, etc., on the booklet 2 and/or the three-dimensional forming part 8. According to this construction, novelty is added to the three-dimensional forming part 3 and an impact or impression can be intensified.