An object is to position a plurality of guide vanes for generating swirl flow at a housing inner circumferential side in front of an impeller wheel to improve a surge margin and to restrict the decrease in a choke flow rate, thereby increasing an operation range of a compressor. A compressor 19 includes a compressor housing 15, an impeller wheel 7 which compresses intake gas flowing in from an intake-air inlet 23, a swirl-flow generating part including a plurality of guide vanes 55 disposed circumferentially along an inner circumferential wall of the intake-air channel 21 between the intake-air inlet 23 and the impeller wheel 7 and which swirls the intake gas from the intake-air inlet 23 around the rotational axis, and a central intake-air flow path 59 formed inside the guide vanes 55 to allow intake gas to flow to the impeller wheel 7 without passing through the guide vanes 55.