Liquid leakage is certainly detected and abnormality in an installation state is detected. A liquid detecting device 10 includes a liquid detection sensor 1 including an insulation sheet 14 exhibiting conductivity in the presence of liquid, electrode members 15 electrically isolated from each other, and a resistance member 18 connected to join the electrode members 15 together. In the liquid detecting device 10, the measurement device 2 measures a value of resistance between the electrode members 15. Based on the value of resistance between the electrode members 15, the liquid detecting device 10 identifies a liquid leakage state in which the insulation sheet 14 exhibits conductivity, a disconnected state in which the electrode members 15 are disconnected from the measurement device 2, and a measurement preparation completed state, and outputs identification information which corresponds to each identified state.
