This paper describes a Mixed Reality installation named Jellyfish Party, for enjoying playing with soap bubbles. A special feature of this installation is the use of a spirometer sensor ti measure the amountand speed of sxpeled air used to blowvirtual soap bubbles. Keywordsmixed reality (MR), soap bubble, spirometer, Jellyfish Party. Jellyfish Party: Blowing Soap Bubbles in Mixed Reality Space Asai Kazuhiro + Canon Inc.