To enable immediate repairing when a failure is generated in a liquid supplying system, and to achieve a stable liquid supplying.

A failure determining apparatus for the liquid supplying system includes: a supply pump 104 for supplying a liquid in a liquid tank to a supplying flow path; a temperature control means 106 for controlling the liquid in the supplying flow path at a predetermined temperature; a plurality of temperature sensors being a plurality of the temperature sensors 100A and 110B capable of measuring the temperature of the liquid after temperature controlling by the temperature control means and equipped respectively at different positions of the liquid supplying system; a temperature acquiring means before supplying the liquid for acquiring the temperature before supplying the liquid at respective positions from a plurality of the temperature sensors before starting to supply the liquid by the supply pump and before starting to control the temperature by the temperature control means; and a temperature acquiring means after supplying the liquid for acquiring the temperature after supplying the liquid at respective positions from a plurality of the temperature sensors after starting to supply the liquid by the supply pump and after starting to control the temperature by the temperature control means, and based on the temperature before supplying the liquid and the temperature after supplying the liquid both acquired, determination of the failure of the liquid supplying system and specification of the position of the failure are performed.