To save the labor for exchange and improve the using efficiency and decrease the space required for storage in a roll for papermaking machine such as a cylinder mold and dandy roll.

A fiber suspension fed in a flat film-like state is gradually dehydrated by natural dehydration, pressure dehydration and suction dehydration while revolving cylindrical suction mold to form a paper layer and the paper layer is transferred to an endless felt by a suction roll and papermaking is carried out. In the above step, a taper suction roll sleeve 6, in which inner peripheral surface has the same gradient as that of outer periphery of taper suction roll cell body and outer peripheral surface is cylindrical, is detached. Thereby, detachment of various kinds of nets rolled on the taper suction roll sleeve 6 can readily be carried out.