PURPOSE: To provide an air-conditioning system which is space-saving and requires seldom maintenance, and in which deodorization and germicidal effect can be achieved with efficiency.

CONSTITUTION: A deodorizing device 7 using a photocatalyst is installed in an air-conditioning duct 11. In addition to and jointly with this deodorizing device a malodorous component-adsorbent device and a light source emitting sterilizing rays or germicidal rays are used; the deodorizing device using a photocatalyst is located inside an air-conditioning duct which is placed in the same space as the air-conditioning apparatus. As a result, without involving enlargement of the air-conditioning apparatus a malodor, etc., contained in the circulating air can be decomposed efficiently and the deodorizing effect can be maintained semipermanently so that an upgrade in both deodorizing effect and germicidal effect can be expected. Moreover, this constitution serves to make an air-conditioning system laborsaving in the aspect of maintenance.