PURPOSE: To attain smooth rotation of flats by eliminating a flat chain of a carding engine and further reducing the number of the flats.

CONSTITUTION: A flat-free space 7 corresponding to about 20-50 flats as the number of flats is arranged in a return transfer passageway of flats above a carding engine by reducing the number of flat and an endless conveyor 10 capable of supporting the end face of flats 1 is stretched at both side of the flat-free space 7 to make a high-speed return transfer passageway of flats. The flats 1 are successively moved onto a flexible bend 2 by cooperation of driving wheels 5 and 6 provided with a sprocket-like sending gear teeth 4 set near the flexible bend 2 by eliminating a flat chain, return flats 1A pushed up by the front driving wheel 5 is successively transferred to the endless conveyor 10 and the transferred flats 1B are transported one by one at high speed to the tail of a reserve flat group IC during dropping toward the flexible bend 2.