Abstract: A first thread of an external screw member is received inside an outlet of the plastic container. The external screw member has a first cylindrical body with a first axial penetrating opening for dispensing contents of the container by passing through the opening. The external screw member is engaged with the internal screw member. The outlet of the plastic container is caught between the external screw member and internal screw member. To easily insert the plastic container, a lower part of the first thread of the external screw member has a larger diameter than an upper part. The second penetrating opening of the internal screw member is opened or closed by opening or closing the covering member. Therefore, the contents of the container can be easily and cleanly dispensed by opening the covering member and then by pouring out the contents. Thereafter the container can be stored with the covering member shut tightly.