A lid and substrate part made of pulp material are connected as one piece via hinge part and configured to be openable and closable, wherein the lid part is provided with a swell part and the substrate part is provided with a part for attaching to a package, a surrounding wall standing from the attaching part and a flange part formed between the surrounding wall and the outlet, wherein when the lid is closed the lid part contacts the flange part, when the closed lid state is maintained the swell part covers the surrounding wall in which a pressing force is applied to the flange part by the lid part, when retention of the closed lid state is removed, the pressing force by the lid part to the flange part is removed and a force to open the lid part is applied from the flange part onto the lid part.