Suction roll for conveying a flexible strip

A roll body has inside a plurality of suction holes extending along the axis of the roll body such that the suction holes make a concentric circle within the roll body and has a large number of pores connecting each suction hole with the circumferential surface of the roll body. A shaft protrudes from the roll body at one side, and the shaft is covered with a housing. The housing is connected with a vacuum suction device, and the air pressure in the housing is negative. In the housing, ends at one side of the suction holes reach the circumferential surface of the shaft, and a belt is wound around the shaft. While the roll body is rotating to convey a strip wound therearound, the belt wound around the shaft opens the ends of suction holes which communicate with pores being in contact with the strip and closes the ends of suction holes which communicate with pores being out of contact with the strip.