First and second shroud surfaces are defined along an imaginary cylinder coaxial to a recording disk. A shroud plate is located between the first and second shroud surfaces. Airflow flows outward along the surface of the rotating recording disk based on the centrifugal force. The shroud plate serves to establish the continuity of the first and second shroud surfaces. The first and second shroud surfaces and the shroud plate serve to reliably suppress turbulence of the airflow. Vibration of the recording disk is suppressed than ever. An inflow opening is located in a space between the first and second shroud surfaces. The rectifier plate is located downstream of the inflow opening. The rectifier plate serves to direct the airflow flowing along the first shroud surface to the inflow opening. A larger amount of airflow can be introduced into the inflow opening. A dust catcher receives airflow of a sufficient amount.