A sheet package is manufactured by folding a thin rectangular package member into a box-like shape and stores a stack of a plurality of cut-sheet type heat-sensitive sheets of small size, for example, of A6 or A7 size. A user purchases a sheet package marketed in a box-like shape, opens a lid portion and folds it back towards a bottom side. Then, an insertion portion of the lid portion is inserted into a slit in the bottom portion of the package member so as to expose sheets stored inside, and the sheets are loaded together with the package member in a sheet storage portion of a printer.