A bottle containing two kinds of materials separately in two spaces in a bottle body and communicates the separated spaces with each other as necessary so that the two materials can be mixed together. This bottle has a bottle body having a mouth; an additive storage container including an insertion part inserted into the mouth, an exposed part exposed outside the mouth and an additive storage space defined therein; an opening unit tightened to the mouth; and separation means for separating the additive storage container from the bottle body. The bottle saves resources and prevents deterioration in the properties in the material and additive. A user can mix the material and additive at a precise ratio, thus preventing their chemical and physical properties from deteriorating. The additive storage container can be completely removed from the bottle body.