PURPOSE: To provide a method for adjusting buoyancy of float, capable of readily controlling buoyancy without requiring preparation of a great number of kinds of sinks and to obtain a float used in the method.

CONSTITUTION: A method for adjusting buoyancy of float controls buoyancy of a float by arranging a sink below and regulating the sink and a float is used for the method. The sink consists of a main sink 12 laid at the lower part of a main body 11 of a float and a granular sink 13 whose stated amount is packed into a space part 12a formed on the top of the main sink 12.