An apparatus for feeding a carding machine with fiber material having a shaft which is fed by a preceding feed shaft. The fiber material is conveyed into the feed shaft by means of a stream of air flowing through a conveying conduit. An air circulating passage is connected between the feed shaft and the filling shaft. An air conveying device is disposed in the air circulating passage for conveying the stream of air emerging from the feed shaft into the filling shaft for compressing the fiber material therein.