In a liquid container used in an automatic analyzer, a float that makes it possible to prevent liquid from making contact with a liquid collection opening of the liquid container to form a film thereon is provided. A float is floated on the liquid surface of a reagent placed in a reagent container for use with an automatic analyzer. The float is equipped with a float body and a required number of buoyancy adjusters. The float body is equipped with a liquid surface cover that covers substantially the entire liquid surface, and a side wall portion positioned so as to project beneath the liquid surface from the liquid surface cover. The side wall portion constitutes a device for the purpose of suppressing swaying motions of the liquid surface cover by making contact with or engaging an inner wall of the reagent container when the reagent sways.