A liquid storage unit, comprising: at least one liquid storage part that stores liquid to be supplied to a liquid ejection part ejecting the liquid and includes an injection port to which the liquid is injectable; a first opening/closing body that is openable so as to cover the injection port when the first opening/closing body is closed; and a locking part that locks the first opening/closing body and keeps the closed state of the first opening/closing body, wherein the first opening/closing body includes a first insertion hole through which a locking member locking the closed first opening/closing body is insertable, and the locking part includes a second insertion hole through which the locking member is insertable, characterized in that: the locking part is provided at a position facing the first insertion hole in an area covered by the closed first opening/closing body, wherein the first insertion hole is provided on a side surface portion on one side in the width direction of the liquid storage unit in the first opening/closing body, wherein in a X-Y-Z coordinate system, an X axis direction indicates the width direction, being a left-right direction, and the direction of moving of the printing head, a Y-axis direction indicates a depth direction, being a front-back-direction, and a Z-axis direction indicates a height direction, being an upper-lower-direction. at least one liquid storage part that stores liquid to be supplied to a liquid ejection part ejecting the liquid and includes an injection port to which the liquid is injectable; a first opening/closing body that is openable so as to cover the injection port when the first opening/closing body is closed; and a locking part that locks the first opening/closing body and keeps the closed state of the first opening/closing body, wherein the first opening/closing body includes a first insertion hole through which a locking member locking the closed first opening/closing body is insertable, and the locking part includes a second insertion hole through which the locking member is insertable, characterized in that: the locking part is provided at a position facing the first insertion hole in an area covered by the closed first opening/closing body, wherein the first insertion hole is provided on a side surface portion on one side in the width direction of the liquid storage unit in the first opening/closing body, wherein in a X-Y-Z coordinate system, an X axis direction indicates the width direction, being a left-right direction, and the direction of moving of the printing head, a Y-axis direction indicates a depth direction, being a front-back-direction, and a Z-axis direction indicates a height direction, being an upper-lower-direction. the locking part is provided at a position facing the first insertion hole in an area covered by the closed first opening/closing body, wherein the first insertion hole is provided on a side surface portion on one side in the width direction of the liquid storage unit in the first opening/closing body, wherein in a X-Y-Z coordinate system, an X axis direction indicates the width direction, being a left-right direction, and the direction of moving of the printing head, a Y-axis direction indicates a depth direction, being a front-back-direction, and a Z-axis direction indicates a height direction, being an upper-lower-direction.