An air-conditioning apparatus for adjusting the direction and quantity of air comprises a duct device forming an air passage passing through the duct device, and an airflow adjusting device. The airflow adjusting device is made from a single thin plate and fitted to the duct device across the air passage to adjust a flow of air. Slits of predetermined patterns are formed on the airflow adjusting device to define a plurality of vanes which are integral to the airflow adjusting device.