A short circuit detection device has a voltage sensor and a control unit. The voltage sensor detects a voltage of a secondary battery. The control unit determines whether a first voltage value of the voltage of the secondary battery discharging to a load is below a threshold value. Upon determining the first voltage value is below the threshold value, the control unit adjusts the load to reduce the current that flows from the secondary battery to the load. The control unit then determines whether a second voltage value of the voltage of the secondary battery after the adjustment of the load is less than the first voltage value. Upon determining the second voltage value is less than the first voltage value, control unit recognizes that an internal short circuit of the secondary battery has occurred.