An air and liquid-tight container is capable of storing different substances in different compartments sealingly separated by a front gasket having two separate parts that are independently slidable. A rear gasket is connectable to a push rod so as to function as a plunger, the front gasket being slidable in response to sliding of the rear gasket, thereby enabling the substance in the rear compartment to be introduced into the front compartment through a bypass. The front and rear gaskets are encased in the tubular body at a compressibility C (%) of 2% to 10%, with the product of the compressibility and the contact area (mm.sup.2) of the gaskets with the inside wall of the tubular wall falling within the range of 150 to 400.