Disclosed is an integrated apparatus for supplying ink and regulating pressure, which comprises a chamber accommodating ink, a main chamber preliminarily storing ink to be supplied to the chamber, a nozzle communicating with the chamber and jetting ink transferred from the chamber to an outside, a first valve blocking or letting flow of ink between the main chamber and the chamber, a second valve blocking and letting flow of ink between the chamber and the nozzle, a piston placed above ink accommodated in the chamber and reciprocating rectilinearly while sealing ink inside the chamber, a piston driver providing a driving force to the piston, a sensor installed in the chamber and sensing pressure due to weight of ink, and a controller receiving a sensed signal from the sensor and outputting a signal for controlling the piston to the piston, wherein the piston moves down as a level of ink accommodated in the chamber is lowered when ink is discharged to the outside through the nozzle, and the piston moves up and the first valve and the second valve are respectively opened and closed when ink is filled in the chamber.