A stopper system including a female member having a conduction path extending in an axial direction thereof, which is to be fixed to a fluid inlet/outlet port of a container, a plug detachably engaged with the tip of the female member, a first male member for supplying a fluid into the container, and a second male member for plugging the conduction path of the female member. Fluid is supplied to the container by inserting the first male member into the conduction path of the female member. The female member is plugged by inserting the second male member into the conduction path of the female member. The fluid in the container is discharged to the outside by inserting a fluid discharge pin into the second male member.