<p>A centrifugal compressor has a diffuser with stator blades (2) arranged therein for converting the kinetic energy of a fluid discharged from an impeller into a pressure energy. The stator blades (2) have leading edges inclined in the downstream direction while extending away from a side plate toward a core plate. Auxiliary blades (4) having a chord length shorter than that of each of the stator blades (2) have leading edges inclined in the downstream direction while extending away from the side plate toward the core plate and are arranged at positions radially inward of the stator blades (2) in such a manner that one of the surfaces of each of the auxiliary blades (4) faces a stator blade (2). The compressor is capable of operating without suffering from surging and rotating stall even in a low flow rate region. <IMAGE></p>
