Various embodiments of the present invention relate to a pouch-type secondary battery having an unsealed portion. The technical purpose to be achieved is to provide a pouch-type secondary battery having an unsealed portion, wherein when gas is generated inside the battery due to overcharging, heat exposure, etc. and the pouch is swelled by the generated gas, the gas can be quickly discharged out of the battery through the unsealed portion, thereby improving safety. To this end, the present invention provides a pouch-type secondary battery comprising: an electrode assembly; and a pouch that comprises a first sheathing portion having a recess in which the electrode assembly is received, a second sheathing portion covering the recess of the first sheathing portion, and a seal portion formed along the peripheries of the first and the second sheathing portions, wherein the seal portion further has at least one unsealed portion connected to the recess, and the unsealed portion is lower than the recess.