To prevent stagnation of a gas flow rising in the vicinity of the inner wall of a tower and to lead a liquid flowing down along the wall of the tower, into a packed material assembly without fail, in a wall flow preventing implement used in a material and/or heat exchange tower.
A wall flow preventing implement 2 is constructed of a wall flow preventing member 1 formed by a method wherein cuts 4 in the longitudinal direction are formed at intervals in the upper part of a belt-like plate material stretching in the circumferential direction along the lateral circumferential edge part of a packed material assembly 1 and cut-formed parts 3 are bent outward. In a belt-like part 7 stretching in the circumferential direction of the wall flow preventing member 1, holes 6 are formed by forming a plurality of cuts 5 and by bending them inward, and cut-formed parts in the belt-like part 7 are joined with the packed material assembly.