An apparatus for detecting a defect of a battery pack including at least one battery cell, comprising: a fuse having one end connected to a first terminal of the battery cell in series and the other end configured to be connected to an electrode terminal of the battery pack; a monitoring unit configured to measure at least one of voltage, current and temperature of the battery cell and determine whether the fuse is cut or not; a discharge line including a discharge resistor having one end configured to be connected to the first terminal of the battery cell in parallel, and a discharge switch having one end configured to be connected to a second terminal of the battery cell and the other end connected to the other end of the discharge resistor; and a control unit configured to receive a measurement result measured by the monitoring unit and a determination result on whether the fuse is cut is not, estimate a state of charge of the battery cell based on the received measurement result, determine based on the received measurement result and the estimated SOC whether a state of the battery cell is a normal state or a defective state, and control an operation state of the discharge switch to a turn-on state or a turn-off state according to the determined state of the battery cell and the determination result on whether the fuse is cut or not, the apparatus for detecting a defect of a battery pack being characterized in that it further comprises: a main switch having one end connected to the other end of the fuse and the other end configured to be connected to the electrode terminal of the battery pack; and a cut-off resistor having one end connected between the fuse and the main switch and the other end connected between the discharge resistor and the discharge switch. a fuse having one end connected to a first terminal of the battery cell in series and the other end configured to be connected to an electrode terminal of the battery pack; a monitoring unit configured to measure at least one of voltage, current and temperature of the battery cell and determine whether the fuse is cut or not; a discharge line including a discharge resistor having one end configured to be connected to the first terminal of the battery cell in parallel, and a discharge switch having one end configured to be connected to a second terminal of the battery cell and the other end connected to the other end of the discharge resistor; and a control unit configured to receive a measurement result measured by the monitoring unit and a determination result on whether the fuse is cut is not, estimate a state of charge of the battery cell based on the received measurement result, determine based on the received measurement result and the estimated SOC whether a state of the battery cell is a normal state or a defective state, and control an operation state of the discharge switch to a turn-on state or a turn-off state according to the determined state of the battery cell and the determination result on whether the fuse is cut or not, the apparatus for detecting a defect of a battery pack being characterized in that it further comprises: a main switch having one end connected to the other end of the fuse and the other end configured to be connected to the electrode terminal of the battery pack; and a cut-off resistor having one end connected between the fuse and the main switch and the other end connected between the discharge resistor and the discharge switch. a main switch having one end connected to the other end of the fuse and the other end configured to be connected to the electrode terminal of the battery pack; and a cut-off resistor having one end connected between the fuse and the main switch and the other end connected between the discharge resistor and the discharge switch.