PURPOSE: To manufacture a roll forming product at low cost at one action from a commercial coil width in the line of one unit by composing the titled device by arranging in a row each roll to straighten the deflection of the metal plate subjected to embossing and to perform a dividing, cutting, forming and to form a striped rib.

CONSTITUTION: The deflection of the thin metal plate A that an uneven patter B is executed on the surface by an embossing roll 5 is straightened by a leveller group 6, divided in (n) by a slit roll 7, formed in the necessary shape by the forming roll groups 8 of plural trains and a striped rib is finally formed on the dressing face of a plate stock A' by a striped embossing roll. The plural trains can be manufactured simultaneously and inexpensively in one action with the roll device of arranging each roll in a line.