PACKING FORMING COMPONENT AND VENTILATION PACKING

PROBLEM TO BE SOLVED: To provide a packing forming component that restricts inflow of mortar, etc. and forms a ventilation packing capable of installing even around a protrusion such as a column, and to provide a ventilation packing.SOLUTION: Packing forming members 6 and 7 are disposed side by side on an upper part of a base 1 to form a ventilation packing 5 interposed between the base 1 and an upper structure 3, and provided with flat plate parts 6a and 7a for receiving the upper structure 3 and ventilation parts 6b and 7b for forming a ventilation passage R on a lower face side of the flat plate parts 6a and 7a. The flat plate parts 6a and 7a are provided with an opening guide part 11 for forming a cutout part C for avoiding a column member 3a which protrudes from the upper structure 3 toward the base 1, and the strength of the opening guide part 11 is weaker than other portions.