An air-conditioning system, comprising: a plurality of indoor units for being installed in a ceiling of an indoor space, the plurality of indoor units each having an indoor casing provided with a plurality of outlet openings (24a to 24d), an airflow direction adjusting flap provided at a corresponding one of the outlet openings (24a to 24d) and configured to change a direction of air blown from the corresponding one of the outlet openings (24a to 24d), and an airflow blocking mechanism provided at a corresponding one of the outlet openings (24a to 24d) for blocking an air current; and a controller configured to control the airflow blocking mechanism in order to perform a partial supply operation in which, in each of the indoor units, the air current coming from one or some of the outlet openings (24a to 24d) is blocked by the airflow blocking mechanism, thereby increasing a speed of the air current coming from the rest of the outlet openings (24a to 24d), wherein the airflow direction adjusting flap is capable of shifting to a position where the air current blown from the corresponding one of the outlet openings (24a to 24d) is blocked, and also serves as the airflow blocking mechanism, characterized in that in the partial supply operation, the controller is configured to set the airflow direction adjusting flaps of one or some of the outlet openings (24a to 24d) to an airflow blocking position, and to set the airflow direction adjusting flaps of the other outlet openings (24a to 24d) to a horizontal airflow position, to control the airflow direction adjusting flaps such that, of the indoor units, regarding the indoor units that are adjacent to each other with a predetermined distance interposed therebetween and each perform the partial supply action, air currents are blown from the outlet openings (24a to 24d) which face each other with the predetermined distance interposed therebetween, so that the air currents collide with each other. a plurality of indoor units for being installed in a ceiling of an indoor space, the plurality of indoor units each having an indoor casing provided with a plurality of outlet openings (24a to 24d), an airflow direction adjusting flap provided at a corresponding one of the outlet openings (24a to 24d) and configured to change a direction of air blown from the corresponding one of the outlet openings (24a to 24d), and an airflow blocking mechanism provided at a corresponding one of the outlet openings (24a to 24d) for blocking an air current; and a controller configured to control the airflow blocking mechanism in order to perform a partial supply operation in which, in each of the indoor units, the air current coming from one or some of the outlet openings (24a to 24d) is blocked by the airflow blocking mechanism, thereby increasing a speed of the air current coming from the rest of the outlet openings (24a to 24d), wherein the airflow direction adjusting flap is capable of shifting to a position where the air current blown from the corresponding one of the outlet openings (24a to 24d) is blocked, and also serves as the airflow blocking mechanism, characterized in that in the partial supply operation, the controller is configured to set the airflow direction adjusting flaps of one or some of the outlet openings (24a to 24d) to an airflow blocking position, and to set the airflow direction adjusting flaps of the other outlet openings (24a to 24d) to a horizontal airflow position, to control the airflow direction adjusting flaps such that, of the indoor units, regarding the indoor units that are adjacent to each other with a predetermined distance interposed therebetween and each perform the partial supply action, air currents are blown from the outlet openings (24a to 24d) which face each other with the predetermined distance interposed therebetween, so that the air currents collide with each other.