A volute of a centrifugal pump includes a proximate section. The proximate section includes: an outer peripheral portion having a tapered shape such that, within a range of a rotational trajectory of each of vanes provided on an impeller, the outer peripheral portion gradually spreads out in a direction axially away from the vane; and an inner peripheral portion having a tapered shape such that, within the range of the rotational trajectory of each of the vanes, the inner peripheral portion tapers in the direction axially away from the vane. The inner and outer peripheral portions are spaced apart from each other with a flat proximal opposed surface portion therebetween. The opposed surface portion is opposed to respective axial end surfaces of vanes of the impeller. The volute also includes a peripheral wall surrounding the peripheral surfaces of the vanes.