A process and apparatus for automatically weighing and introducing chemicals are intended to automatically weigh the chemicals and introduce the chemicals into a treatment tank; the chemicals are injected into a chemical container and weighted, and then transported to a dissolving tank adjunct to the treatment tank, and then introduced into the dissolving tank. A control means is provided to put under its control the operations of injecting into a chemical container a desired amount of desired chemicals selected from among plural sorts of chemicals and driving a transportments and an introducing means automatically in association with this injecting operation.