A centrifugal compressor comprising: a housing including: an air intake port open in a direction of a rotational shaft of the centrifugal compressor; and an air intake path connected to the air intake port; an impeller which is disposed in the housing and compresses intake gas flowed in through the air intake port, the impeller being rotatable about the rotational shaft; a reverse swirling flow generation unit which is disposed between the air intake port and the impeller in the housing and wherein the reverse swirling flow generation unit is attached by being inserted from the side of the air intake port along an inner peripheral wall of the air intake path, and wherein the reverse swirling flow generation unit generates a swirling flow of the intake gas, flowed in through the air intake port, in a direction opposite to a rotation direction of the impeller; and a recirculation flow path which communicates between an outer circumferential portion of the impeller with the air intake path on an upstream side of the impeller, wherein the reverse swirling flow generation unit includes a reverse swirling fixed blade which generates a swirling flow at a predetermined angle with respect to the direction opposite to the rotation direction of the impeller and a cylindrical member forming the recirculation flow path, the reverse swirling fixed blade is disposed at a portion of the air intake path between a flow inlet and a flow outlet of the recirculation flow path, the reverse swirling fixed blade being attached on an inner peripheral wall of the cylindrical member, the reverse swirling fixed blade radially extending in radial direction, and the reverse swirling fixed blade and the cylindrical member are formed as an integral structure, a tilt angle of a downstream end of the reverse swirling fixed blade is set to be a predetermined angle within a range of 5° to 45° with respect to the direction opposite to the rotation of the impeller, and wherein a strut or a protrusion is disposed in the recirculation flow path (82; 102), the strut or the protrusion changing a flow direction of a circulation flow to the direction opposite to the rotation direction of the impeller and protruding on an outer circumference surface of the cylindrical member, or wherein a strut extending along the direction of the rotational shaft is disposed in the recirculation flow path (82; 102), and 5 to 20 or preferably 10 to 15 of the protrusions are disposed along the circumferential direction. a housing including: an air intake port open in a direction of a rotational shaft of the centrifugal compressor; and an air intake path connected to the air intake port; an impeller which is disposed in the housing and compresses intake gas flowed in through the air intake port, the impeller being rotatable about the rotational shaft; a reverse swirling flow generation unit which is disposed between the air intake port and the impeller in the housing and wherein the reverse swirling flow generation unit is attached by being inserted from the side of the air intake port along an inner peripheral wall of the air intake path, and wherein the reverse swirling flow generation unit generates a swirling flow of the intake gas, flowed in through the air intake port, in a direction opposite to a rotation direction of the impeller; and a recirculation flow path which communicates between an outer circumferential portion of the impeller with the air intake path on an upstream side of the impeller, wherein the reverse swirling flow generation unit includes a reverse swirling fixed blade which generates a swirling flow at a predetermined angle with respect to the direction opposite to the rotation direction of the impeller and a cylindrical member forming the recirculation flow path, the reverse swirling fixed blade is disposed at a portion of the air intake path between a flow inlet and a flow outlet of the recirculation flow path, the reverse swirling fixed blade being attached on an inner peripheral wall of the cylindrical member, the reverse swirling fixed blade radially extending in radial direction, and the reverse swirling fixed blade and the cylindrical member are formed as an integral structure, a tilt angle of a downstream end of the reverse swirling fixed blade is set to be a predetermined angle within a range of 5° to 45° with respect to the direction opposite to the rotation of the impeller, and wherein a strut or a protrusion is disposed in the recirculation flow path (82; 102), the strut or the protrusion changing a flow direction of a circulation flow to the direction opposite to the rotation direction of the impeller and protruding on an outer circumference surface of the cylindrical member, or wherein a strut extending along the direction of the rotational shaft is disposed in the recirculation flow path (82; 102), and 5 to 20 or preferably 10 to 15 of the protrusions are disposed along the circumferential direction.