PURPOSE: To enhance carrying performance for foods such as seaweed, unrefined sake and the like by letting each outer end of blades be forcively and slidably brought into contact with the inner circumferential wall of a casing by means of roller member in a rotary pump in which a space between the casing and a rotor is partitioned into plural working chambers by the blades.

CONSTITUTION: A rotor 20 housed in a rotor chamber 11 is formed into a circular shape, and is disposed upward while being eccentric with respect to the center of the rotor chamber, so that it is thereby rotatably supported by a drive shaft integrally provided for its rear section. The rotor 20 is formed with a communicating chamber 22 at its center, and with four guide grooves 23 extended from the communicating chamber 22 in the radial direction, and blades 30 made of resin are fitted in each groove 23 in such a way as to be freely moved in the radial direction. In addition, the communicating chamber 22 of the rotor 20 is provided with a thick cylindrical roller member 41 made of resin in such a manner that it can be rotated roughly around the rotor chamber by means of a hollow roller shaft 42. By this constitution, each outer end of the blades is pressed onto the inner circumferential wall of a rotor housing so as to be slidably brought into contact with the wall when the rotor 20 is rotated.