To provide a double suction centrifugal pump having less reduced pump efficiency by varying a flow amount with a change of a required liquid amount as keeping a pump head unchanged.

The double suction centrifugal pump comprises two impellers, namely, a first centrifugal impeller 1A and a second centrifugal impeller 1B mounted on a pump spindle 2 in a simultaneously rotatable manner and housed in a pump casing 3 in a rotatable manner. Herein, a communication passage 16 is provided between a second suction flow path 4B communicated with an inlet 1b of the second centrifugal impeller 1B and a discharge casing 6. A previous turn imparting means 20 consists of an impeller train 22 for imparting the communication passage 16 previous turn S1 in the same direction as a rotating direction R of the second centrifugal impeller 1B, and a communication passage opening/closing means 30 consists of a shutter plate 31 for opening/closing the communication passage 16.