A rapping device is provided for forming a battery separator or the like by rapping from a flexible elastic band material. A rapping device for manufacturing works in a specified shape by rapping from an elastic band material comprises a conveying drum having a first suction unit and a second suction unit for conveying the band material while suction is applied, a die drum having a blade possessing a forming position for rapping and forming the works with a width coinciding with the width of the band material, and a cutting position for cutting between the adjacent works, disposed continuously on the outer circumference at every pitch equal to the length of each work, and a die drum driving device for rotating and driving the die drum in synchronization with the conveying speed of the band material.