Abstract: A centrifugal compressor includes a rotary blade that is rotatable around an axis. The centrifugal compressor includes an inlet part that extends in the axial direction, that forms an inlet passage to introduce gas to the rotary blade, and that includes a circular cross section. The centrifugal compressor includes a projecting part that projects from a part of a circumferential wall surface of the inlet passage. A top end of the projecting part is located within an inflow region through which gas flows to the rotary blade. An inclined surface of the projecting part is formed to be inclined so that the top end of the projecting part is located downstream in a rotation direction of the rotary blade relative to a base end of the projecting part.