A packaging box, for a golf ball, is formed by folding a packaging sheet
comprising a decomposable laminate material consisting of a polylactic
acid-containing polymer film and a sheet of paper laminated with the
polylactic acid-containing polymer film. A portion corresponding to a
window is cut out from the paper, and the window is covered with the
polylactic acid-containing polymer film laminated on the paper. The window
is formed straddlingly on two or three planes such that the polylactic
acid-containing polymer film covering the window is bent perpendicularly
at a boundary between the planes adjacent to each other. A raised portion
is formed on the packaging sheet.
