In a liquid supply apparatus, a liquid held in a liquid holding portion is pushed out to the exterior by pressurized gas. The apparatus includes a liquid pouring section for pouring a predetermined amount of liquid into an intermediate portion of the liquid holding portion, a liquid discharge portion which comprises a thin pipe smaller in flow passage cross-sectional area than the liquid holing portion, and is connected to one end of the liquid holding portion, a liquid storing portion which is larger in flow passage cross-sectional area than the liquid holding portion, and is connected to the other end of the liquid holding portion, and a gas feed section for feeding the pressurized gas into the liquid storing portion. The apparatus further includes at least one of first fault detection section for detecting a fault of the liquid pouring section and second fault detection section for detecting a fault of the gas feed section.