To prevent contamination of a clean room even if a paper tube is brought into the room by using dust-free paper having specific number or blow of particles each having a specific particle size or below per one cubic foot for the tube.

The dust-free paper tube is set to 1,700 or below pieces of of particles each having a particle size of 0.3 μm or above per one cubic foot (0.02832 m2) by using dust-free paper of natural pulp made of wood fiber, bast fiber, fine Japanese paper fiber or the like, synthetic fiber such as nylon fiber, rayon fiber or the like, and synthetic pulp represented by fibrillated polyethylene. Thus, even if the tube is brought into a clean room, a contamination of the room can be prevented. When an outermost surface is spirally wound up so as to be partly superposed and then a protrusion formed by the superposition is cut to manufacture the tube, a soft film or the like can be wound on the tube without causing winding mark of the tape-like paper.