Use of an ink refill container configured to refill ink to an ink tank (41-45), wherein the ink tank includes: an ink storage chamber configured to store ink; a needle that extends in an upward direction and that includes a flow passage in communication with the ink storage chamber; an ink inlet in which the needle is arranged; and a receiving surface having the ink inlet, the receiving surface extending along a direction intersecting the needle extending direction; wherein the ink refill container comprising: a container main body including an ink container chamber configured to contain the ink; an ink outlet-forming portion that is provided on an end portion of the container main body, the ink outlet-forming portion having an ink outlet that allows the ink to flow out from the ink container chamber; and a valve provided in the ink outlet-forming portion, the valve configured to be opened by the needle inserted into the ink outlet; wherein the ink outlet-forming portion includes a positioning portion , the positioning portion provided at a position on an outer side of the ink outlet-forming portion, the positioning portion being closer to the container main body than the valve is to the container main body in a central axis direction of the ink outlet, when the needle is inserted into the ink outlet , the valve is opened and the positioning portion abuts against the receiving surface . wherein the ink tank includes: an ink storage chamber configured to store ink; a needle that extends in an upward direction and that includes a flow passage in communication with the ink storage chamber; an ink inlet in which the needle is arranged; and a receiving surface having the ink inlet, the receiving surface extending along a direction intersecting the needle extending direction; an ink storage chamber configured to store ink; a needle that extends in an upward direction and that includes a flow passage in communication with the ink storage chamber; an ink inlet in which the needle is arranged; and a receiving surface having the ink inlet, the receiving surface extending along a direction intersecting the needle extending direction; wherein the ink refill container comprising: a container main body including an ink container chamber configured to contain the ink; an ink outlet-forming portion that is provided on an end portion of the container main body, the ink outlet-forming portion having an ink outlet that allows the ink to flow out from the ink container chamber; and a valve provided in the ink outlet-forming portion, the valve configured to be opened by the needle inserted into the ink outlet; wherein the ink outlet-forming portion includes a positioning portion , the positioning portion provided at a position on an outer side of the ink outlet-forming portion, the positioning portion being closer to the container main body than the valve is to the container main body in a central axis direction of the ink outlet, a container main body including an ink container chamber configured to contain the ink; an ink outlet-forming portion that is provided on an end portion of the container main body, the ink outlet-forming portion having an ink outlet that allows the ink to flow out from the ink container chamber; and a valve provided in the ink outlet-forming portion, the valve configured to be opened by the needle inserted into the ink outlet; wherein the ink outlet-forming portion includes a positioning portion , the positioning portion provided at a position on an outer side of the ink outlet-forming portion, the positioning portion being closer to the container main body than the valve is to the container main body in a central axis direction of the ink outlet, when the needle is inserted into the ink outlet , the valve is opened and the positioning portion abuts against the receiving surface . <EOS>