To improve unsealability and mold release characteristics by providing a cut portion surrounding a thin weak line ring on a seal plate on a lower part of the inside of a pour-out cylinder, by making a pillar having a pull ring on an upper end stand along an inner periphery of the cut portion and also by applying crimps on an internal face of the pull ring.

The pour-out port device 100 comprises a flange 120 and a pour-out cylinder 110 having a threaded portion 111 with a cap, while a cut portion 240 surrounding a thin weak line ring 131 is provided on a seal plate 130 on a lower part of the pour-out cylinder 110 and also a pillar 150 having a pull ring 160 at an upper end is provided on an inner periphery of the cut portion 140. Crimps are applied on an internal face 161 of the pull ring 160. Thus, mold release characteristics can be improved when the pour-out port device 100 is to be injection-molded using polyethylene. In addition, when a paper container for liquid with the pour-out port device 100 attached is to be unsealed, a finger tip can be hooked on the pull ring 160 without being slipped, thereby insuring easy and smooth unsealing.