A second sealing film is thermally bonded onto a leading end portion of an ink lead-out member of an ink pack and an annular projecting portion provided on an ink casing. Thereby, a gap produced between the ink lead-out member and the ink casing can be closed from outside the ink casing. Accordingly, the air tightness of a space in the ink casing is kept, thus making it possible to raise the pressure in the space and generate such a force as to crush the ink pack.