PURPOSE: To facilitate the operation of installing an air conditioner by con- stituting the framework for installing the air conditioner to be fitted to window by a fixed framework along the side wall of the air conditioner and a sliding frame incorporated slidably in the fixed frame, and providing sealing materials on the outer side surfaces of the fixed frame and sliding frame, respectively.

CONSTITUTION: The fixed frame 3 of a substantially square-shape is fastened by a screw 7 to the side wall of an air conditioner 2 through a support plate 6. The sealing material 8 is bonded to the entire length of the side wall of the substantially channel shaped sliding frame 4, and thus the sliding frame 4 is slidably inserted through the fixed frame 3. Further, the sealing material 9 is engaged with a part of the fixed frame 3 opposing to the sealing material 8 of the sliding frame 4. By this construction, the entire length of the side walls of the sliding frame 4 and fixed frame 3 are sealed with the sealing materials 8 and 9, and the sealing property can be secured with respect to the sliding movement of the sliding frame 4. Thus, the titled framework can be freely adjusted according to the dimension of the window frame, and further after- fitting of the sealing material becomes unrequired, thus facilitating the operations.