PROBLEM TO BE SOLVED: To provide a seal structure of an oxygen capsule capable of appropriately preventing air leakage.SOLUTION: A seal structure of a soft-type oxygen capsule 1 includes an outside faster 20 attached to a capsule body 10, a seal member 40 for covering at least a reverse surface part of the outside faster 20, a support member 50 provided on the reverse side of the outside fastener 20 for supporting the seal member 40 from the reverse side, and an inside fastener 30 attached to the support member 50. The inside fastener 30 is provided to the support member 50 in a state that the opening/closing part 32 does not come in contact with the seal member 40, and, in a closed state, causes the seal member 40 to come in contact with the outside fastener 20.SELECTED DRAWING: Figure 7【課題】空気漏れを好適に防止できる酸素カプセルのシール構造を提供する。【解決手段】ソフトタイプの酸素カプセル1のシール構造であって、カプセル本体10に取り付けられる外側ファスナー20と、外側ファスナー20の裏面部を少なくとも覆うシール部材40と、外側ファスナー20の裏側に設けられ、シール部材40を裏側から支持する支持部材50と、支持部材50に取り付けられる内側ファスナー30とを備え、内側ファスナー30は、その開閉部分32がシール部材40と当接しない状態で支持部材50に設けられ、かつ閉状態のときにシール部材40を外側ファスナー20に当接させる。【選択図】図7