Abstract: A stopper for a container including a stopper body provided with an inlet port at the lower end thereof and an outlet port communicating with the inlet port at the front end thereof. A guide cylinder extends from a wall above the inlet port within the stopper body and a push rod extends through and beyond either side of the guide cylinder. The push rod is provided with a valve body for opening and closing the inlet port at a lower end thereof and a receiving seat at an upper end thereof. A spring is disposed between the wall above the inlet port and the receiving seat for biasing the push rod upwardly. A lever is arranged to pivot about a hinge positioned in the front part of the stopper body at the same level or below the upper end surface of the push rod when said valve body is in a position at which it closes the inlet port.