A faulty cell detection device and a faulty cell detection method are provided for detecting a faulty cell of a battery pack using a current sensor. The device may include a current sensor including a first current sensor configured to measure a current of a battery pack including the battery module, and a second current sensor configured to measure a current of a battery cell among battery cells in the battery module. The device may also include a faulty cell detector configured to detect occurrence of the faulty cell based on the measured current of the battery pack and the measured current of the battery cell.