PURPOSE: To prevent the ink filling volume in each ink container from being fluctuated by applying appropriate pressure to ink with an ink pressurizing and filling device and press-filling ink in the front end of each ink container via a center hole of a pipe and elastic sheet material.

CONSTITUTION: An ink container 11 whose circumferential surface of an occludent polyester resin fiber bundle 9 is coated with vinyl chloride nonaqueous film 10 is cut to the predetermined length. A pressurizing unit 8 is advanced to contact the rear end of the ink container 11 and then, the front end of the ink container is advanced to contact the side of an elastic seal material 7 with the pressure of about 3 kg so that the end portion of a coating 10 of the ink container 11 may be slightly embedded in the circumferential portion of a center hole 6 of the elastic seal material, 7 to be sealed. Thereafter, 1000 mg of ink are press-filled in the front end of the ink container 11 via an ejection pipe 5 and the center hole 6 of the elastic seal 7 which is driven by an ink pressurizing and filling apparatus 4 at the filling speed of about 2000 mg/s (flow rate).