Provided is a secondary battery, including a bare cell including a terrace-shaped part on a side thereof; an insulation film attached to the terrace-shaped part; and a thermal protection device on the insulation film. The thermal protection device includes a transfer part; and a first lead terminal and a second lead terminal on both sides of the transfer part. The insulation film includes an opening overlapping the transfer part. The transfer part directly contacts the terrace-shaped part through the opening.