An apparatus and method for detecting a defective battery cell is proposed. The proposed apparatus includes a charger for supplying current to cause a battery cell to maintain a constant voltage, a measurement part for measuring the voltage and current of the battery cell, and a controller for determining whether a defect exists in the battery cell on the basis of the current measured by the measurement part, whereby the defective battery cell may be detected with high accuracy, a time required for the detection may be shortened, and a space required for the detection may also be reduced.