The present invention provides a storing structure for storing an ink jet head comprising a nozzle communicated with an opening for discharging liquid, a liquid storing portion for storing the liquid to be supplied to the nozzle, and a liquid introduction portion for introducing the liquid into the liquid storing portion from exterior, wherein, in the ink jet head, air is housed in the liquid storing portion and the liquid is contained at least in the nozzle, and a cap unit including an elastic cap for covering an area of the opening and a liquid absorbing member disposed in the elastic cap is closely contacted with and attached, around the opening, to a face in which the opening is formed, and the liquid introduction portion is communicated with atmosphere at least when inner pressure of the liquid storing portion is increased, thereby maintaining a space within the cap unit to a wetting condition.