Lid, mold, and lid manufacturing method

A lid comprising:

• a circular top portion including a drinking hole at a peripheral portion thereof, at least a portion of the top portion having the drinking hole having a flat shape;
• a fitting portion including an inner fitting portion and an upper fitting portion,
• the inner fitting portion protruding upwardly from a peripheral end of the top portion and adapted to contact a rim-side inner circumferential surface of a container body, the inner fitting portion having an outer diameter equal to an inner diameter of the rim-side inner circumferential surface of the container body and the inner fitting portion having a same inclination angle as that of the rim-side inner circumferential surface of the container body, such that, at least in a state where the inner fitting portion is attached to the container body, the inner fitting portion contacts with the rim-side inner circumferential surface of the container body,
• the upper fitting portion being thicker than the inner fitting portion and adapted to be fitted onto a rim of the container body,
• an upper end of the fitting portion being at a level higher than the drinking hole;
• and
• a skirt portion,
• an upper end of the skirt portion being continuous with an outer-side lower end of the fitting portion,
• the skirt portion extending downwardly away from the rim of the container body,
• the skirt portion has a tapered shape which increases in diameter in a radially outward direction from the upper end of the skirt portion to a lower end of the skirt portion;
• and
• the skirt portion being adapted to cover a rim-side outer circumferential surface of the container body;
• wherein the skirt portion has an uneven shape to enhance buckling strength;
• and
• a plurality of concave portions, separate from the uneven shape, are provided between the upper fitting portion and the skirt portion, with one of the plurality of concave portions overlapping the drinking hole in a radial direction of the circular top portion.