An ink cartridge includes an ink storage chamber for storing ink provided therein. The ink cartridge is mountable to an inkjet recording apparatus. The inkjet recording apparatus includes: a door disposed on of an accommodating chamber defining a space for accommodating the ink cartridge and allowing the ink cartridge to be mounted thereto in the horizontal direction through a first opening and configured to be rotated about the lower side of the accommodating chamber as an axis of rotation for opening and closing the first opening and closing the first opening when it takes an upright posture; and a pressing member provided on the door for pressing a back surface of the ink cartridge inserted into the accommodating chamber by a resilient force. The ink cartridge comprising: (a) an ink supply part provided on a front side surface being defined in a mounting direction when the ink cartridge is in a mounted posture, which is a posture when the ink cartridge is mounted to the accommodating chamber, and having a second opening for allowing entering of an extracting member of the inkjet recording apparatus when being mounted to the inkjet recording apparatus; (b) a supply valve mechanism for opening and closing the second opening of the ink supply part; and (c) a pressed portion provided on a back surface at the rear side in the mounting direction when the ink cartridge is in the mounting posture and configured to be pressed by the pressing member. The supply valve mechanism includes a supply valve member for opening and closing the second opening of the ink supply part and a supply urging member for urging the supply valve member to a direction of closing the second opening of the ink supply part. The urging force of the supply urging member is adapted to be smaller than the resilient force of the pressing member for pressing the pressed portion.