PURPOSE: To provide a safe ink tank wherein ink does not leak even when vibration and shock are applied.

CONSTITUTION: An ink tank 14 comprises an outside air communicating unit 1404 for communication of the inside with the outside air and contains ink. The outside air communicating unit 1401 has a plurality of chambers which communicate with each other from the inside to the outside. Openings of the chambers are small in proportion to the chamber. The chambers are positioned in the direction crossing the direction from the inside to the outside. The openings of the chambers are arranged in positions deviated from each other.