An airflow-guiding device (40) is secured at one side of a row of fans (20) in a computer chassis (10) and is capable of allowing air to flow therethrough in one direction only. The airflow-guiding device includes a bracket (42) and a plurality of shielding plates (44). The bracket is secured in the chassis and defines a plurality of guideways (428) therein. The shielding plates are pivotably secured in the guideways with shafts (442) thereof, respectively. The shaft of each of the shielding plates separates the corresponding plate into two portions. One of the two portions is larger and weightier than the other of the two portions.