DETERIORATION DETERMINATION SUPPORT DEVICE, WATER ELECTROLYSIS DEVICE, AND DETERIORATION DETERMINATION SUPPORT METHOD

A deterioration determination support device 40 includes: a first calculating unit 42 that acquires a dataset including a plurality of reaction condition values and voltages relating to water electrolysis reaction of a water electrolysis module 2, which have been measured in a first period, and in a second period following the first period, or derived from measured values, and uses the dataset and a predetermined calculation expression to calculate a parameter group for the calculation expression for each period; a second calculating unit 44 that substitutes predetermined reaction condition values into the calculation expression into which the parameter group is incorporated, and calculates a comparison object value for each period; and a third calculating unit 46 that calculates a degree of deterioration of the water electrolysis module 2 on the basis of difference between a first comparative object value calculated by the calculation expression into which the parameter group for the first period is incorporated, and a second comparative object value calculated by the calculation expression into which the parameter group for the second period is incorporated.