a casing including:

a casing lower part formed by an alternating sequence of four side parts and four corner parts,

main outlets disposed along each of said side parts,

an inlet surrounded by all of said side parts, and

auxiliary outlets disposed at at least one of said four corner parts; and

horizontal flaps rotatably supported about longitudinal axes of said main outlets configured to vary a wind direction of an air current blown out from each of said main outlets, the wind direction of the air current blown out from each of said main outlets being variable within an angular range relative to a lower surface of a ceiling to which the air conditioner is mounted, the angular range being defined between a first direction inclined a first angular amount relative to the lower surface and a second direction inclined a second angular amount relative to the lower surface,

each of said auxiliary outlets having a circumferential edge part formed so that air is blown out from each of said auxiliary outlets in a fixed direction,

the fixed direction being substantially equally angularly spaced from the first and second directions such that the fixed direction is substantially in a middle of the angular range within which the wind direction of the air current blown out from each of said main outlets is variable.