An ink cartridge includes a case, and the case includes a first case member. The first case member includes a first wall, and the first wall includes a translucent portion extending from the first wall in a predetermined direction. The translucent portion has an inner space formed therein. The case also includes a second case member connected to the first case member. The first case member and the second case member define an ink chamber therein, and the second case member includes a second wall which is opposite to the first wall, and a support member connected to an interior surface of the second wall. Moreover, the ink cartridge includes a movable member which includes a signal blocking portion. The signal blocking portion is positioned within the inner space of the translucent portion, and the movable member is connected to the support member.