A centrifugal compressor 10 includes a diffuser 13 that comprises: a shroud wall surface 131 that extends in the radial direction of a rotating shaft 3; and a hub wall surface 132 that extends in the radial direction and opposes the shroud wall surface 131 on the downstream side of a flow in the axial direction of the rotating shaft 3, the hub wall surface having a gap between itself and the shroud wall surface 131, and with that gap, forming an annular diffuser flow path 130 through which a fluid flows. A hub-side convex portion 132b is formed over the entire periphery of the hub wall surface 132, the hub-side convex portion 132b protruding toward the shroud wall surface 131 side relative to a straight line L1 that connects a starting end 132s on an inlet 130a side of the diffuser flow path 130 and a terminating end 132e on an outlet 130b side of the diffuser flow path 130.