Capsule containers disclosed in the present invention. In principle, the capsule container is accommodated inside of the opening formed in a common container such as a beverage container, bucket container, etc. and caught and supported by the rim of the opening. The capsule container is advantageous in that it enables blending of the content accommodated inside with a fluid, powder, etc. having different properties as intended by the user; safe blending of contents without flowing-out; and prevention of excessive flow-out of contents as only proper amounts of the contents are discharged through the opening when the contents flow out.