To provide a centrifugal volute pump capable of preventing the rotation of an impeller from being blocked due to a solid matter bitten into a gap between a front blade and a front cover, and also capable of preventing a suction port from being blocked due to a solid matter caught in a portion between main blades at the suction port.

The centrifugal volute pump includes closed type impellers (7; 7A-7H). Front blades are not formed at front covers (8; 8A, 8B) sides of side walls (3; 3A, 3B) of the impeller. End faces of the side walls (3; 3A, 3B) at the front cover sides and end faces at front cover side walls are machined to have smooth surfaces. A mechanism which does not allow a solid matter to enter a gap (δb, δc) is formed between the side walls and the front covers.