To prevent the end surface of an opened mouth of a cap fitting part from being soiled with ink for a writing utensil even when the ink storing container is upset in the state of having a cap thereon in the ink storing container wherein the ink for the writing utensil is stored in the inside thereof and the cap is screw-fitted with the cap fitting part protruded on a container body having a pen point protecting adapter having an ink retaining part retaining the ink for the writing utensil.

A lid stopper 25 constituted by a stopper part 24 water-tightly closing the mouth 16 of the container body 2 and an insertion part 22 insertable into the cap fitting part 4 and having an abutting part 27 water-tightly abutting on an inner wall surface of the cap fitting part 4 and slidable thereto on an outer side surface 26 is fixed on an inner side of the cap 3.