To provide a volute pump reliably pumping water when an operation is started, easy to manufacture and having high quality by providing a priming faucet on an intake passage and a deaerating plug on a discharge passage, and forming the priming faucet and the deaerating plug with the same component.

A casing cover 2 forming a water passage to cover an impeller 12 a directly connected to a motor shaft 10 is provided, and an intake passage 13 and a discharge passage 14 are communicated to it to form a water passage. The intake passage 13 is provided with a priming port 20a having a removable faucet 35, the discharge passage 14 is provided with a deaerating port 22 having a removable deaerating plug 36, and the faucet 35 and the deaerating plug 36 are formed with the same component. Even when a pump is started while little water is left to separate the air in the impeller 12a and the discharge passage 14, the air in the discharge passage 14 is deaerated by the deaerating port 22 on the discharge passage 14, and priming can be applied to the passage to an opening section 14 a from a bulkhead 19. A volute pump reliably pumping water at the start of an operation and having high quality and high productivity can be obtained.