An electrolyte concentration measurement device includes: an ion-selective electrode supplied with the liquid; a reference electrode serving as a reference for a potential; a potential measuring unit configured to acquire a potential of the ion-selective electrode; a concentration calculation unit configured to calculate a concentration of ions contained in the liquid based on the potential acquired by the potential measuring unit; a potential monitoring unit configured to monitor a potential of the ion-selective electrode and generate a potential response curve; a timing signal acquisition unit configured to acquire a timing signal related to a timing of various operations; and a potential response curve analysis unit configured to detect an abnormality sign of a device based on a relationship between the potential response curve and the timing signal.