A liquid-holding container , comprising: a liquid container portion that is flexible and configured to contain a liquid; a hollow vent plug that is connected to the liquid container portion; and a first projecting portion that is provided outside the liquid container portion and connected to the vent plug, the first projecting portion extends in a direction that intersects a face of the liquid container portion; and the liquid-holding container further comprises a second projecting portion that is provided outside the liquid container portion and connected to the vent plug on the opposite side of the vent plug from the first projecting portion, the second projecting portion extending in the direction that intersects the face of the liquid container portion, such that the second projecting portion is opposite the first projecting portion, characterised in that the second projecting portion extending in the same direction as the extending direction of the first projecting portion, wherein a first length (L2) is shorter than a second length (L1), the first length (L2) being a length of the second projecting portion from a plane that includes an axis (X) of the vent plug to a leading end of the second projecting portion, the second length (L1) being a length of the first projecting portion from the plane that includes the axis (X) of the vent plug to a leading end of the first projecting portion, the leading end of the second projecting portion and the leading end of the first projecting portion being positioned at the same side with respect to the plane that includes the axis (X) of the vent plug . a liquid container portion that is flexible and configured to contain a liquid; a hollow vent plug that is connected to the liquid container portion; and a first projecting portion that is provided outside the liquid container portion and connected to the vent plug, the first projecting portion extends in a direction that intersects a face of the liquid container portion; and the liquid-holding container further comprises a second projecting portion that is provided outside the liquid container portion and connected to the vent plug on the opposite side of the vent plug from the first projecting portion, the second projecting portion extending in the direction that intersects the face of the liquid container portion, such that the second projecting portion is opposite the first projecting portion, characterised in that the second projecting portion extending in the same direction as the extending direction of the first projecting portion, wherein a first length (L2) is shorter than a second length (L1), the first length (L2) being a length of the second projecting portion from a plane that includes an axis (X) of the vent plug to a leading end of the second projecting portion, the second length (L1) being a length of the first projecting portion from the plane that includes the axis (X) of the vent plug to a leading end of the first projecting portion, the leading end of the second projecting portion and the leading end of the first projecting portion being positioned at the same side with respect to the plane that includes the axis (X) of the vent plug . <EOS>