An abnormality detection device includes: a voltage value acquisition unit configured to acquire a voltage value of each battery cells, a state value measurement unit configured to measure a state value inside a battery pack, which is different from a temperature of each battery cell, and an abnormality determination unit configured to determine an abnormality of the battery pack. The abnormality determination unit includes: a voltage value comparison unit configured to compare the voltage value with a predetermined voltage threshold value, and a state value comparison unit configured to compare at least one of the state value and a degree of change in the state value per unit time with a predetermined state threshold value. The abnormality determination unit is configured to determine an abnormality of the battery pack based on both a voltage value comparison result and a state value comparison result.