An ink tank includes a detector element that optically detects a condition of ink. The ink tank includes a first ink chamber adapted to be opened to an external environment. A second ink chamber communicates with the first ink chamber and includes a bottom surface with protrusions. A third ink chamber is disposed below the second ink chamber relative to a direction of gravity. The ink tank also includes an ink passage by which the second ink chamber communicates with the third ink chamber. An ink outlet communicates with the third ink chamber. The detector element is arranged so as to face at least one of the ink passage and the third ink chamber.