A bag-like container comprising: a bottom sheet including a first paper base layer and a heating element layer configured to generate heat by absorbing electromagnetic waves, a first resin film layer provided between the first paper base layer and the heating element layer, a first seal layer provided on the heating element layer; a top sheet bonded to the bottom sheet in such a manner as to be separable from the bottom sheet with a content to be cooked being contained, wherein the top sheet is configured to transmit the electromagnetic waves, the top sheet including a second paper base layer provided on an outermost face side, a second resin film layer provided on the second paper base layer, a second seal layer provided on the second resin film layer, the second seal layer being thermally bonded to the first seal layer; wherein the bag-like container includes a seal portion provided along a periphery of the bottom sheet and the top sheet, the seal portion being configured to heat-seal the first seal layer and the second seal layer; each of the bottom sheet and the top sheet forms a rectangular shape; the bottom sheet includes a non-heating portion provided along two opposed sides in the periphery, wherein the non-heating portion is configured to transmit the electromagnetic waves; characterized in that a part of the seal portion includes a relief portion configured to form an unsealing base point for the bottom sheet and the top sheet, to be arranged at the non-heating portion, and to be placed in one corner of each of the bottom sheet and the top sheet in such a manner as to be inclined relative to two adjacent sides in the corner. a bottom sheet including a first paper base layer and a heating element layer configured to generate heat by absorbing electromagnetic waves, a first resin film layer provided between the first paper base layer and the heating element layer, a first seal layer provided on the heating element layer; a top sheet bonded to the bottom sheet in such a manner as to be separable from the bottom sheet with a content to be cooked being contained, wherein the top sheet is configured to transmit the electromagnetic waves, the top sheet including a second paper base layer provided on an outermost face side, a second resin film layer provided on the second paper base layer, a second seal layer provided on the second resin film layer, the second seal layer being thermally bonded to the first seal layer; wherein the bag-like container includes a seal portion provided along a periphery of the bottom sheet and the top sheet, the seal portion being configured to heat-seal the first seal layer and the second seal layer; each of the bottom sheet and the top sheet forms a rectangular shape; the bottom sheet includes a non-heating portion provided along two opposed sides in the periphery, wherein the non-heating portion is configured to transmit the electromagnetic waves; characterized in that a part of the seal portion includes a relief portion configured to form an unsealing base point for the bottom sheet and the top sheet, to be arranged at the non-heating portion, and to be placed in one corner of each of the bottom sheet and the top sheet in such a manner as to be inclined relative to two adjacent sides in the corner.