To provide a method and a apparatus for manufacturing a medicine treatment liquid which can be prepared from crystalline powder or raw liquid without polluting surrounding environment.

In a method for manufacturing a compounded medical liquid by injecting a medicine in a vessel accommodating the medicine into a liquid medicine compounding tank, a medicine injection port of the medical liquid compounding tank and an opening of the vessel are joined to each other via a cylindrical body equipped with a lid body capable of opening or closing and the opening of the vessel is opened to inject the medicine into the medical liquid compounding tank.