| 摘要 |
The present invention provides a container opening, which has been made more lightweight while ensuring good sealability. The inner circumferential surface of this container opening (11) is provided with a thin-walled section (11b) extending from a position on the leading edge-side of an area, which contacts an inner ring (24) when a cap (20) is fitted, to the leading edge. The thin-walled section (11b) has at least a first thin-walled part (11b1) formed toward the base and a second thin-walled part (11b2), which is formed toward the leading edge and has a different shape from the first thin-walled part (11b1). The first thin-walled part (11b1) is formed with a curved surface that is convex toward the inside. |
