To provide a lid that securely tightly covers the top of the container, is also easily opened/closed and, moreover, allows an opened lid-portion to be easily and securely locked to a fixed lid-portion.

The lid is designed so as to be freely bent along a given cross- line that crosses a plane. Also, the lid has locking portions for locking both the component parts of the lid, between which there is the crease as their boundary, over the corresponding container openings so that, with the lid fitted over the opening of the container, one of the lid component parts is fixed and the other is opened/closed. In such a lid, an adhesive layer is provided on part of the upper face of at least one of the lid component parts. Thus, when the lid component part on the opened/closed side is bent onto the lid component part on the fixed side, the adhesive layer detachably connects both the lid component parts. In addition, the adhesive layer is covered with a strip of peelable sheet.