<p>The inner bottom (222b) of a female-like projection (22b) is continuously provided with an elastic viscous material (4) along the longitudinal direction so as to bulge into a space defined between the hooks (221b, 221b) of the female-like projection (22b). When a male-like projection (21a) fits in the female-like projection (21b), the elastic viscous material (4) is pressed onto the head (221a) of the male-like projection (22a) so as to be abutted against the head (221a) of the male-like projection (22a) while undergoing elastic deformation, and intimately contacts the surface of the front end of the head (221a) by the viscous force and elastic force, whereby the air-tightness of the chuck-equipped bag can be secured.</p>
