An ink tank is provided which can efficiently perform detection of information in an ink tank such as an ink residual amount in the ink tank with a simple configuration in which it is unnecessary to set wiring or the like. A solid semiconductor element, which is provided with an acquiring unit for acquiring environmental information of the outside, an information storing unit, a discriminating unit for comparing acquired information and stored information to make a determination, and an information communicating unit for displaying the acquired information or communicating the acquired information to the outside, is embedded in an outer wall of an ink tank such that the solid semiconductor element is exposed to an internal side and an external side of the ink tank from the outer wall. The solid semiconductor element can perform supply of its operation energy or exchanges of signals in a non-contact state or by connecting with a terminal provided in a supporting portion or the like of the ink tank directly, thus, it is unnecessary to set wiring. In this case, the information acquiring means can be preferably disposed in the part of the solid semiconductor element exposed to the inside of the ink tank.