An ink refilling container, comprising: a bottle; and a cap configured to be put on the bottle detachably; the bottle including an ink outlet forming portion that includes an ink outlet, a valve provided inside the ink outlet and an outer circumferential portion, the ink outlet having a cylindrical shape, the outer circumferential portion having a first thread portion, wherein the valve is made of an elastic material and includes valve segments segmented by at least one slit extending in a radial direction from a center of the ink outlet toward an outer circumference; the cap including a barrel portion having a cylindrical shape and including an inner circumferential portion on which a second thread portion configured to engage with the first thread portion is formed; and a top portion configured to face the ink outlet when the cap is put on the bottle; wherein a protruding portion extending in a direction of a central axis of the barrel portion is provided at a center of the top portion, a sealing portion having an annular shape is provided on the top portion outside the protruding portion in the radial direction, a radius of the protruding portion is set to be less than a length of the slit as viewed in a direction of a central axis of the ink outlet when the valve is closed, and in a sealed state in which the cap is in thread engagement with the bottle and in which the sealing portion seals the ink outlet, a tip end of the protruding portion is inserted in an inside of the bottle through the slit at a center region of the ink outlet as viewed in the direction of the central axis of the ink outlet, and characterized in that the protruding portion has a plurality of small protruding portions that constitute the tip end thereof, the small protruding portions axially extending in the direction of the central axis of the barrel portion from a cylindrical wall of the protruding portion and arranged at equal intervals in the circumferential direction, the protruding portion pushes down the valve segments and the tip end of the protruding portion is located more inside of the bottle than ink-outlet-center-side ends of the pushed valve segments in the sealed state. a bottle; and a cap configured to be put on the bottle detachably; the bottle including an ink outlet forming portion that includes an ink outlet, a valve provided inside the ink outlet and an outer circumferential portion, the ink outlet having a cylindrical shape, the outer circumferential portion having a first thread portion, wherein the valve is made of an elastic material and includes valve segments segmented by at least one slit extending in a radial direction from a center of the ink outlet toward an outer circumference; the cap including a barrel portion having a cylindrical shape and including an inner circumferential portion on which a second thread portion configured to engage with the first thread portion is formed; and a top portion configured to face the ink outlet when the cap is put on the bottle; wherein the bottle including an ink outlet forming portion that includes an ink outlet, a valve provided inside the ink outlet and an outer circumferential portion, the ink outlet having a cylindrical shape, the outer circumferential portion having a first thread portion, wherein the valve is made of an elastic material and includes valve segments segmented by at least one slit extending in a radial direction from a center of the ink outlet toward an outer circumference; the cap including a barrel portion having a cylindrical shape and including an inner circumferential portion on which a second thread portion configured to engage with the first thread portion is formed; and a top portion configured to face the ink outlet when the cap is put on the bottle; wherein a barrel portion having a cylindrical shape and including an inner circumferential portion on which a second thread portion configured to engage with the first thread portion is formed; and a top portion configured to face the ink outlet when the cap is put on the bottle; wherein a protruding portion extending in a direction of a central axis of the barrel portion is provided at a center of the top portion, a sealing portion having an annular shape is provided on the top portion outside the protruding portion in the radial direction, a radius of the protruding portion is set to be less than a length of the slit as viewed in a direction of a central axis of the ink outlet when the valve is closed, and in a sealed state in which the cap is in thread engagement with the bottle and in which the sealing portion seals the ink outlet, a tip end of the protruding portion is inserted in an inside of the bottle through the slit at a center region of the ink outlet as viewed in the direction of the central axis of the ink outlet, and characterized in that the protruding portion has a plurality of small protruding portions that constitute the tip end thereof, the small protruding portions axially extending in the direction of the central axis of the barrel portion from a cylindrical wall of the protruding portion and arranged at equal intervals in the circumferential direction, the protruding portion pushes down the valve segments and the tip end of the protruding portion is located more inside of the bottle than ink-outlet-center-side ends of the pushed valve segments in the sealed state.