An ink-jet image forming device includes: an ink flow path; a degassing unit provided in the middle of the ink flow path including a gas-permeable degassing membrane one surface of which is brought into contact with ink in the ink flow path; a vacuum sucker that evacuates the degassing unit; and a vacuum path connecting the vacuum sucker and the degassing unit, wherein the vacuum path is arranged so as to evacuate on a surface side opposite to a surface side brought into contact with the ink of the degassing membrane in the degassing unit, a storage space for storing an inflow flowing into the degassing membrane and the vacuum path is included in the middle of the vacuum path, and the storage space may be maintained at a raised temperature by a heat source.