This deterioration estimation device is provided with: an SOH acquisition unit which acquires the SOH of a power storage element at a first time and the SOH at a second time after the first time; and a learning processing unit which trains a learning model on the basis of learning data which, as input data, includes time series data relating to the state of the power storage element from the first time to the second time, and the SOH at the first time and, as output data, includes the SOH at the second time.