Air conditioner

An air conditioner comprising:

• a first air conditioning unit disposed in a first space formed between a first ceiling and a second ceiling that is spaced downward from the first ceiling and lower than the first ceiling, the first air conditioning unit being configured to suction air from a second space that is recessed from the second ceiling toward the first ceiling;
• a second air conditioning unit, disposed in the first space, to communicate with the first air conditioning unit, the second air conditioning unit being configured to discharge air introduced from the first air conditioning unit;
• and
• a guide device configured to guide at least one of the first air conditioning unit and the second air conditioning unit along a guide rail installed on the first ceiling to move from the first space toward the second space or to move from the second space toward the first space,
• wherein the first air conditioning unit and the second air conditioning unit are detachably coupled to each other, and
• the air conditioner further comprises a locking device configured to couple the first air conditioning unit to the second air conditioning unit.