To provide a device for evaluating the capacity of an electrode active material, whereby the capacity of only an active material in an electrode can be accurately evaluated.

This device includes a charging means, a voltage detecting means 5 for detecting the voltage changes of a cell having an operating electrode, a counter electrode and a reference electrode connected in parallel to the charging means, a voltage waveform storing means 7 for storing the voltage changes detected by the voltage detecting means 5 in sequence to feedback the storage signal to the charging means 2, a current detecting means 10 for detecting the current changes of the cell having the operating electrode, the counter electrode and the reference electrode connected in parallel to the charging means 2 and a current waveform storing means 14 for storing the current changes detected by the current detecting means 10 in sequence.