This disclosure discloses an ink cartridge comprises a housing; a reservoir portion disposed so that an end portion on one side in a thickness direction contacts the housing; a detection plate that is supported with respect to the housing at a lower end portion, comes in contact with the other side of the reservoir portion in the thickness direction, and rotates in accordance with an ink volume, thereby executing a display in accordance with the ink volume by that rotational position; and a collapse prevention rib that creates a predetermined gap between an end portion on one side in the thickness direction and a left wall portion of the housing, extends above the detection plate, and causes the upper portion of the reservoir portion to be inserted through the gap, thereby suppressing the displacement of the reservoir portion to the other side in the thickness direction.