To avoid creating wrinkles and yield no embossing luster unevenness at the time of forming recessed patterns on an olefin resin sheet and manufacturing a decorative sheet.

A sheet is heated little by little by a number of heating rolls 14a-14i, and after passing through the last roll 14i, it is heated abruptly by a short wave length heater 20 to be in a semi-molten state to subsequently be held between the impression cylinder 16 and the embossing roll 17, and concurrently be cooled abruptly. Even in the event of effecting embossing work on an olefin resin sheet having the nature of thermal expansion in the width direction, no wrinkles are created in the direction of flow, and embossing luster unevenness is also never generated thereon.