A gas-collecting apparatus for collecting gas generated in a secondary battery comprising an electrode assembly and a flexible pouch case accommodating the electrode assembly therein, wherein the pouch case includes a first sheet covering one surface of the electrode assembly and a second sheet covering the other surface of the electrode assembly, wherein the gas-collecting apparatus comprises: an insert plate part in close contact with the first sheet inside the pouch case; a pressing jig part in close contact with the insert plate part outside the pouch case with the first sheet interposed therebetween, the pressing jig part contacting and pressing only a local area of the secondary battery, wherein the insert plate part includes a through hole penetrating the insert plate part so that a first surface of the insert plate part facing the first sheet and a second surface opposite to the first surface are connected to each other, and wherein a gas moving path of which one end is connected to the through hole and through which the gas generated in the secondary battery flows is formed inside the pressing jig part; a punching part inserted into the through hole from the outside of the pouch case for forming a ventilating hole in the first sheet, wherein the ventilating hole allows the gas to be discharged to the outside of the pouch case and to flow into the gas moving path; and a supporting jig part facing and being in close contact with the pressing jig part with the secondary battery interposed therebetween, outside the pouch case. wherein the pouch case includes a first sheet covering one surface of the electrode assembly and a second sheet covering the other surface of the electrode assembly, wherein the gas-collecting apparatus comprises: an insert plate part in close contact with the first sheet inside the pouch case; a pressing jig part in close contact with the insert plate part outside the pouch case with the first sheet interposed therebetween, the pressing jig part contacting and pressing only a local area of the secondary battery, wherein the insert plate part includes a through hole penetrating the insert plate part so that a first surface of the insert plate part facing the first sheet and a second surface opposite to the first surface are connected to each other, and wherein a gas moving path of which one end is connected to the through hole and through which the gas generated in the secondary battery flows is formed inside the pressing jig part; a punching part inserted into the through hole from the outside of the pouch case for forming a ventilating hole in the first sheet, wherein the ventilating hole allows the gas to be discharged to the outside of the pouch case and to flow into the gas moving path; and a supporting jig part facing and being in close contact with the pressing jig part with the secondary battery interposed therebetween, outside the pouch case. an insert plate part in close contact with the first sheet inside the pouch case; a pressing jig part in close contact with the insert plate part outside the pouch case with the first sheet interposed therebetween, the pressing jig part contacting and pressing only a local area of the secondary battery, wherein the insert plate part includes a through hole penetrating the insert plate part so that a first surface of the insert plate part facing the first sheet and a second surface opposite to the first surface are connected to each other, and wherein a gas moving path of which one end is connected to the through hole and through which the gas generated in the secondary battery flows is formed inside the pressing jig part; a punching part inserted into the through hole from the outside of the pouch case for forming a ventilating hole in the first sheet, wherein the ventilating hole allows the gas to be discharged to the outside of the pouch case and to flow into the gas moving path; and a supporting jig part facing and being in close contact with the pressing jig part with the secondary battery interposed therebetween, outside the pouch case.