To stably keep assembly of an article storage cap of an over cap structure with a can container; to prevent pressure difference from occurring between the inside and the outside of the cap thereby safely protecting a stored article against working depression load; and to keep a combination of the can container and the cap and the assembled single cap easy to handle.

The topped cylindrical article storage cap 1 to be fitted over the can container 11 has a plurality of locking protrusions 5 to come beyond and lock with a peripheral rib 14 provided at equal intervals at the lower end of the inner peripheral surface of a cylindrical wall 2 having a slightly larger inner diameter than the outer diameter of the peripheral rib 14 of the can container 11. A longitudinally protruding strut piece 8 for bringing the lower end surface 9 into contact with the upper surface of the peripheral rib 14 while the locking protrusion 5 locks with the peripheral rib 14 and having a thickness exhibiting a large withstand load strength is provided immediately above the protrusion 5, for safely storing and holding the stored article.