PURPOSE: To allow a tube diaphragm pump to have a simple structure and be miniaturized by including a chemical-resistant cylinder forming an internal space that sucks or delivers fluid according to hydraulic pressure, an elastic cylinder surrounding the outside of the chemical-resistant cylinder, and a pressure transfer medium packed between the cylinders.

CONSTITUTION: This tube diaphragm pump includes a chemical-resistant cylinder 3 provided to surround the central axis of a pump main body 2 and forming therein a space 24 for sucking and discharging liquids, and an elastic cylinder 4 provided to surround the outside of the chemical-resistant cylinder 3. The chemical-resistant cylinder 3 and the elastic cylinder 4 are fixed at both end openings of the pump main body 2 by means of fixing members 5. When a liquid in a hydraulic pressure chamber is pressed by a suction and pressure means, the elastic cylinder 4 shrinks accordingly. The shrinkage of the elastic cylinder 4 results in the application of pressure to a pressure transfer medium packed between the elastic cylinder 4 and the chemical-resistant cylinder 3. The tube diaphragm pump thus has a simple structure and can easily be miniaturized.