A liquid jetting apparatus includes: a head; an ink storage chamber communicating with the head; a gas distributing chamber in which a gas introducing hole is formed; a buffer chamber in which a communicating hole for communicating with the gas distributing chamber, and an atmosphere opening hole for opening to the atmosphere are formed; a combination valve which is capable of opening and closing the gas introducing hole and the communicating hole; a gas introducing mechanism which introduces the compressed air through the gas introducing hole to the head to jet the ink forcibly, and a positive-pressure control valve which opens the atmosphere opening hole when a pressure in the buffer chamber exceeds a predetermined value. It is possible to operate a positive-pressure purge while suppressing an excessive increase in the pressure inside the liquid storage chamber, without increasing a size and a cost of the apparatus.