Abstract: A deterioration inspection apparatus according to an embodiment disclosed herein includes a controller configured to obtain, at a first timepoint, first data related to a first open circuit voltage (OCV) and a first state of health (SoH) of a battery and obtain, at a second timepoint, second data related to a second OCV and a second SoH of the battery, identify a theoretical capacity of the battery at a reference timepoint from reference data related to the battery, calculate an OCV change amount between the first OCV and the second OCV and an SoH change amount between the first SoH and the second SoH and calculate an anode side reaction (ASR) and a cathode side reaction (CSR) at the second timepoint, based on the theoretical capacity of the battery, the OCV change amount, and the SoH change amount.