There is provided a liquid discharge apparatus including a liquid jet head, and a liquid supply unit configured to supply the first liquid to the liquid jet head. The liquid supply unit includes an atmosphere connection portion having a containment portion, an atmosphere communication membrane, and a second liquid contained in the containment portion. The atmosphere connection portion is configured to let the second liquid depart from at least a part of the atmosphere communication membrane under a condition that nozzles of the liquid jet head are positioned above a liquid connection portion of the cartridge installation portion, and is also configured to let the second liquid cover the entire area of the atmosphere communication membrane under a condition that the nozzles of the liquid jet head are positioned below the liquid connection portion of the cartridge installation portion.