Condition monitoring system for metal recovery device

Provided is a system for monitoring the condition of a metal recovery device. The condition monitoring system comprises a metal recovery device and a control device. The metal recovery device comprises a voltage measurement unit for measuring the voltage between a negative electrode and a positive electrode. The control device comprises a data calculation unit for processing measured voltage data received from the voltage measurement unit. The data calculation unit calculates, as a feature amount, a derivative value on the basis of the voltage data, compares the feature amount against a prescribed threshold value, and when the feature amount is the threshold value or greater, diagnoses the positive electrode as being in a maintenance-required state.