Airtight performance test apparatus according to an aspect of the invention is provided with the opening border of the structure capable of adjustable length the first rectangular frame and the first projecting one end is connected respectively to each edge surface of a rectangular frame and a number that can be adjustable of the connecting frame, and a second rectangular frame in which each corner is connected respectively to the other end of the connection frame and the is provided in the interior of the second rectangular frame and a blower unit for supplying the wind to the first square boxes direction, of the second rectangular frame When equipped with the first contact of the supporter for supporting the second rectangular frame, one end connected to the said second rectangular frame the other end becomes abutted to the wall surface facing the said opening milchal the border the opening of said first rectangular frame rod, wherein the square boxes of the first rim, the connecting frame, are provided in the form covering the border of the second rectangular frame may include sealing the film to reach the wind does not escape to the outside opening portion supplied from the blower unit.