To provide a package reducing the cost and the time, and using not only for an envelope and packaging, but also for a pentagonal advertisement medium or the like.

In a rectangle ABCD, the ratio of AB:BC is set to be about 1:1.026. Points E and F on BC and DA are determined so that the angle ∠BEF formed by the line segment EF passing through the center O of the rectangle and the ridge BC is about 54°. The points G and H are determined to substantially trisect the line segment EF. The points I, J, K, L on the ridges BC, AB, CD and DA are determined so that the angles ∠HGI, ∠GHJ, ∠HGK and ∠GHL form about 108°, respectively. The points M and N on the ridges AB and CD are determined so that the angles ∠BIM and ∠DLN form about 18°, respectively. The line segments GH, IG, HJ, GK, HL, IM and LN are folded in the ridge, and the line segments EG and FH are folded in the valley to constitute a pentagonal package.