An eccentric screw pump with an annular outer part (10; 40; 74) and an inner part (12; 42; 72) arranged therein has an interior of the outer part (10; 40; 74) and an exterior of the inner part (12; 42; 72) tapering in a complementary manner towards an axial end (16; 46; 70). In the axial direction (X, W), the inner part (12; 42; 72) and the outer part (10; 40; 74) are movably received in relation to each other and the inner part (12; 42; 72) and/or the outer part (10; 40; 74) are configured in such a manner that pressure applied to the pressure side of the eccentric screw pump generates a force that acts upon the inner part (12; 42; 72) axially to the direction in which the inner part (12; 42; 72) tapers and/or a force that acts upon the outer part (10; 40; 74) in an opposite axial direction.