A supercharging air compressor for an internal combustion engine, having a compressor wheel which is rotatably mounted in a compressor inlet duct, and to which combustion air can be fed via the compressor inlet duct. A partial stream of the compressed supercharging air is branched off downstream of the compressor wheel and is fed to a temperature reducing unit. The branched-off partial stream is fed, as cooling air, to a component of the supercharging air compressor after it has flowed through the temperature reducing unit.