To provide a cap with a metallic ring 1, structured such that an insertion attaching part 7a of a metallic ring 7 attached to a cap body 40 is hardly seen through as a belt-like shadow even when the metallic ring 7 is stuck to an opening 41 of the cap body 40 with a transparent adhesive 9.

A plurality of annular protrusions 7c, configured such that the width W1 of a flat surface 7f formed on a top 7e in a direction along a shaft center is 0.1 mm or less, are formed at nearly equal intervals in the direction along the shaft center on an outer surface of the insertion attaching part 7a of the metallic ring 7, and the insertion attaching part 7a of the metallic ring 7 is stuck to an insertion attachment receiving part 41a of the cap body 40 with the transparent adhesive.