Abstract: [Object] To provide a synthetic resin cap of a structure that is further improved in convenience when drinking while suppressing falling or loss of the cap when a container is opened. [Solving Means] A synthetic resin cap as a specific example of the present invention has a tamper-evident band to be fitted on an outer peripheral surface of a container mouth portion of a container, and a cap main body having a skirt wall and a top plate, and including, in the skirt wall, a fixing rib coupled with the tamper-evident band via a weakened portion and a strap portion and extending to a radially outer side of the skirt wall. The fixing rib is formed from a first inclined portion that flares downwards, and a protrusion portion that is disposed below the first inclined portion.

Abstract: A hinge cap includes a body and an upper lid connected to each other by a hinge. The body includes a top board and a side wall extending perpendicularly downward from a periphery of the top board. The top board includes a planned opening defined by a weakened portion and a discharge nozzle formed to surround the planned opening. The upper lid includes a top panel and a skirt extending perpendicularly downward from a periphery of the top panel. A protrusion extending in an axial direction of the cap is formed in the planned opening of the body on a side opposite to the hinge such that an end of the protrusion is fixed to an inner surface of the top panel of the upper lid in a closed state.