PURPOSE: To simply, efficiently inspect drain discharge of an air conditioner installed at a high place such as a ceiling, etc., or a place having a small service space.

CONSTITUTION: When generated drain water B is fed into a transparent drain hose 6 through a drain pump 5, it is identified by a transparent peep hole 9 of a service panel 10 to inspect an operation of the pump. When adhered dye adhered to an outer frame of the pump and solid dye arranged on a drain pan are dissolved and solution liquid is fed into the hose through the pump, it is identified via the hole of the panel to inspect the operation of the pump. Further, a rotation of an impeller to be rotated by a water flow by the hose is identified via the hole of the panel to inspect the operation of the pump.