PURPOSE: To provide a pump for conveying fluid which is constituted to convey high velocity fluid, such as miso (soybean paste), continuously and smoothly through a long pipe.

CONSTITUTION: A piston 30 has a rear end formed in the shape of a cylinder sealed with a bottom wall 32 the inner surface 32a of which is recessed in a funnel-shape. A drill bit 34 is helically reversely to a belt vane 16 wound around the peripheral part of an inner cylinder 12 into which a piston 30 is inserted. The front end opening part 36 of the piston is cut obliquely approximately in the same direction as the inclination direction of the drill bit 34. An air discharge port 38 is opened to the bottom of the inner surface 32a of a piston bottom wall and an air feed means 90 through which air is intermittently fed is coupled to the air discharge port 38. Further, the inner peripheral surface of the inner cylinder 12 is formed in a cylindrical shape, the piston 30 is rotatably coupled to moving means 40 and an air feed means 90, and the piston 30 is brought into a state to be rotatable in the inner cylinder 12.