PURPOSE: To modify a sticking surface to form a non-sticking surface by forming a thermoplastic high molecular membrane on the sticking surface of a reinforcing fiber base material containing a viscous liquid or soft solid curable resin.

CONSTITUTION: By the use of an opening cylindrical device 4 consisting of an opening cylindrical member 20 and a support member 21, a flattened cylindrical reinforcing fiber base material 2 is expanded in its radius direction by the action of the opening cylindrical member 20 inserted in the base material 2 to be formed into a hollow cylindrical article A. Since the hollow cylindrical article A is pulled by the tensile force in the right direction to be moved to the right, the opening cylindrical member 20 also receives external force in the right direction and the tapered leading end part thereof is fitted in the communication hole 23 of the support member 20 and the opening cylindrical member 20 is supported. Since the cylindrical article A moved to the right is pressed between the opening edge part 24 of the support member 21 and the outer peripheral surface of the leading end of the opening cylindrical member 20, an excessive resin soln. is removed. By this constitution, the surface of a conventional surface sticking prepreg is formed into a non-sticking surface.