To provide an Wesco pump capable of reducing pulsation of a fluid discharged out of a discharge opening and reducing the pump noise caused by the pulsation.

The pump comprises an impeller 10 with a blade groove 10a arranged in the circumferential direction to be driven to rotate and a pump casing 6. A pump channel 12 corresponding to the blade groove 10a of the impeller is formed in the pump casing 6, and the pump casing 6 also has a suction opening 16a and the discharge opening 18c communicating with the pump channel 12. Two branched channels including pumping processes based on the rotation of the impeller 10 respectively are formed in the pump channel from the suction opening 16a to the discharge opening 18c. The branched channels are jointed so that the pulsation of the fluid discharge from each pumping process is offset.