A centrifugal compressor comprising: a rotary shaft which is configured to rotate around an axis; impellers which are arranged to form a plurality of stages with respect to the rotary shaft in an axis direction and are configured to pressure-feed a fluid flowing in from an inlet on one side in the axis direction to an outside in a radial direction; and a casing which surrounds the rotary shaft and the impellers and has an intermediate flow path through which the fluid discharged from a preceding stage impeller of the impellers adjacent to each other is introduced into a subsequent stage impeller and a suction-and-discharge flow path which connects the intermediate flow path and an outside to each other, wherein the suction-and-discharge flow path includes a circumferential flow path which extends in an arc shape about the axis in a circumferential direction of the axis and communicates with the intermediate flow path in the circumferential direction, and an external communication path which is connected to both circumferential ends of the circumferential flow path and communicates with the outside, wherein the circumferential flow path has a uniform flow path cross-sectional area in the circumferential direction, wherein a convex curved surface having a convex curved surface shape continuous to an inner wall surface of the external communication path when viewed in the axis direction is provided between an outer peripheral wall surface of the circumferential flow path and the inner wall surface of the external communication path, and characterized in that in a case where, when viewed in the axis direction, a curvature radius of the convex curved surface is defined as R and a radial dimension of the circumferential flow path is defined as W, a relationship of W ≤ R ≤ 3W is established. a rotary shaft which is configured to rotate around an axis; impellers which are arranged to form a plurality of stages with respect to the rotary shaft in an axis direction and are configured to pressure-feed a fluid flowing in from an inlet on one side in the axis direction to an outside in a radial direction; and a casing which surrounds the rotary shaft and the impellers and has an intermediate flow path through which the fluid discharged from a preceding stage impeller of the impellers adjacent to each other is introduced into a subsequent stage impeller and a suction-and-discharge flow path which connects the intermediate flow path and an outside to each other, wherein the suction-and-discharge flow path includes a circumferential flow path which extends in an arc shape about the axis in a circumferential direction of the axis and communicates with the intermediate flow path in the circumferential direction, and an external communication path which is connected to both circumferential ends of the circumferential flow path and communicates with the outside, wherein the circumferential flow path has a uniform flow path cross-sectional area in the circumferential direction, wherein a convex curved surface having a convex curved surface shape continuous to an inner wall surface of the external communication path when viewed in the axis direction is provided between an outer peripheral wall surface of the circumferential flow path and the inner wall surface of the external communication path, and characterized in that in a case where, when viewed in the axis direction, a curvature radius of the convex curved surface is defined as R and a radial dimension of the circumferential flow path is defined as W, a relationship of W ≤ R ≤ 3W is established.