PURPOSE: To enable arbitrary increase of a specified wall thickness size depending upon the thickness of an installation wall, by a method wherein an installation auxiliary tool, serving to extend the length of a cabinet, is located between a front panel and a body, and the front panel and the body are intercoupled through the installation auxiliary tool to insert a window type air conditioner into a mounting hole for support.

CONSTITUTION: In case a window type air conditioner 11 is installed to a wall having thickness thicker than a specified wall thickness size L, an installation auxiliary tool 15, being arbitrarily removable depending upon the wall thickness, is located between the air conditioner body 11 and a front panel 14, and this enables increase of the specified wall thickness size L through extension of the length of a cabinet 16. A simpl e work only to secure the installation auxiliary tool 15 to the upper surface of the cabinet 16 by means of screws 34 enables the window type air conditioner 11 to be installed to a wall 35 having a wall thickness (t) exceeding the specified wall thickness size l of an air conditioner body 12, and eliminates an additional work, such as an increase in the width of a mounting hole 37, resulting in improvement of installation efficiency.