An ink cartridge for printers and ink filling method that can expand the space where the ink is filled, and maintain pressure inside the ink cartridge. The ink cartridge includes a body formed in a predetermined shape and having a filling hold on one surface, a filling chamber where ink is filled inside the body, a discharging chamber connected to the filling chamber, an ink discharging port connected to the discharging chamber through an ink transferring channel, an air chamber connected to the filling chamber to supply air through an air transferring channel, an air suction valve in the air chamber, an air inducing channel that induces exterior air into the air suction valve, a blocking film attached to one surface of the body, a cover installed on another surface of the body, a pressure regulating part on one surface of outer body, which communicates with the filling chamber.