An eccentric screw-type pump has a pump section with a tubular pump casing, a stator cladding and a pump cavity (30) configured in correspondence with a double-thread or multi-thread screw. A screw-type rotor is connected to a driving shaft via a flexible shaft. The flexible shaft is connected at its two ends via rigid coupler elements to the rotor and the driving shaft, and is surrounded by a preloaded coaxially disposed screw.