A liquid container configured to be mountable to and dismountable from a case of a liquid ejection device, wherein a direction parallel to direction of gravity is defined as a Z direction, wherein a direction of the Z direction that is identical with the direction of gravity is defined as a +Z direction and a direction of the Z direction that is opposite to the direction of gravity is defined as a -Z direction; a direction orthogonal to the Z direction is defined as a Y direction, wherein one direction of the Y direction is defined as a +Y direction and the other direction of the Y direction is defined as a -Y direction; and a direction orthogonal to the Z direction and the Y direction is defined as an X direction, wherein one direction of the X direction is defined as a +X direction and the other direction of the X direction is defined as a -X direction, the liquid ejection device comprising: a housing with a case placement unit provided inside thereof the case configured to move along the +Y direction to be inserted into the case placement unit, the case including a bottom surface arranged to face in the -Z direction and two guide elements protruded in the -Z direction from the bottom surface in a state that the case is placed in the case placement unit; a liquid introducing element located at a +Y direction side end of the case placement unit; and a device-side electrical connecting structure located at the +Y direction side end of the case placement unit, the liquid container comprising: a bag-like member that has flexibility and that includes a containing portion provided inside thereof to contain a liquid therein; and a connection member that is located at a +Y direction side end in a mounting state that the liquid container is mounted to the liquid ejection device, wherein the connection member comprises: a liquid outlet configured such that a liquid introducing element of the liquid ejection device is insertable into the liquid outlet in the -Y direction, in the mounting state; a container-side electrical connecting structure configured such that the device-side electrical connecting structure is connectable with the container-side electrical connecting structure in the -Y direction, in the mounting state; and characterized by two guided elements of the case configured such that at least respective parts of the two guide elements are fittable in the two guided elements, in a state that the liquid container is placed in the case, wherein in the mounting state, the liquid outlet is located between the two guided elements in the X direction, and the container-side electrical connecting structure is located between one of the two guided elements and the liquid outlet, the two guided elements being provided in first and second surfaces (125, 126), respectively, that are arranged on the +X and -X side, respectively. a bag-like member that has flexibility and that includes a containing portion provided inside thereof to contain a liquid therein; and a connection member that is located at a +Y direction side end in a mounting state that the liquid container is mounted to the liquid ejection device, wherein the connection member comprises: a liquid outlet configured such that a liquid introducing element of the liquid ejection device is insertable into the liquid outlet in the -Y direction, in the mounting state; a container-side electrical connecting structure configured such that the device-side electrical connecting structure is connectable with the container-side electrical connecting structure in the -Y direction, in the mounting state; and characterized by two guided elements of the case configured such that at least respective parts of the two guide elements are fittable in the two guided elements, in a state that the liquid container is placed in the case, wherein a liquid outlet configured such that a liquid introducing element of the liquid ejection device is insertable into the liquid outlet in the -Y direction, in the mounting state; a container-side electrical connecting structure configured such that the device-side electrical connecting structure is connectable with the container-side electrical connecting structure in the -Y direction, in the mounting state; and characterized by two guided elements of the case configured such that at least respective parts of the two guide elements are fittable in the two guided elements, in a state that the liquid container is placed in the case, wherein in the mounting state, the liquid outlet is located between the two guided elements in the X direction, and the container-side electrical connecting structure is located between one of the two guided elements and the liquid outlet, the two guided elements being provided in first and second surfaces (125, 126), respectively, that are arranged on the +X and -X side, respectively.