An ink supplying and collecting device for an ink reservoir formed between a main roll for applying an ink to a plate cylinder and an auxiliary roll in contact with the main roll, the device being adapted to supply the ink to the ink reservoir by causing the ink to flow out from a nozzle extending downward as directed toward the ink reservoir while moving the nozzle in parallel to axia direction of the rolls, and to collect the ink by lowering the nozzle to a position close to the bottom of the ink reservoir and drawing up the ink with the nozzle while moving the nozzle in parallel to the axial direction of the rolls. The device comprises a closed pressure container movableby a drive unit in parallel to the rolls for removably accommodating an ink tank therein, a nozzle unit hermetically inserted in the container and having one end loosely extending through an opening of the ink tank to a position close to the bottom of the tank and the other end providing the nozzle, and a pressurizing unit and a pressure reducing unit switchably connected to the container. When supplying the ink, the internal pressure of the container and the tank is increased by the pressurizing unit to a level higher than atmospheric pressure to cause the ink in the tank to flow out from the nozzle. When collecting the ink, the pressure reducing unit gives a negative internal pressure to the container and the tank, causing the nozzle to draw up the ink from the reservoir and collect the ink into the tank.