PURPOSE: To provide a continuously preformed sheet for forming a large quantity of mail letters and an apparatus for molding it.
CONSTITUTION: A paper web is constituted of a divisible end supply part surrounding a continuously preformed sheet, which has opposed pair of lateral cutting lines 26, 28 extended from web ends 20, 22 at a uniform interval in a lengthwise direction, the pair of the lines are cut, a center 30 of the one web 10 is retained without cutting, and further lines extended from the ends 38, 40 have the same length. Lines 32, 34 formed with perforations and knurls are fed longitudinally along lateral ends extended from the ends 38, 40. Before forming mail letter of the form in which the web 10 is cut at opposed paired lines or mail letter of the divided and superposed form, the continuous form sheet 24 of the web 10 can be superposed in a direction for moving the web 10 at a shortest interval.