Air conditioner

An air conditioner that includes an indoor unit having an indoor heat exchanger, an outdoor unit having an outdoor heat exchanger connected to the indoor heat exchanger through a refrigerant pipe, and an outside casing housing at least the outdoor unit and is attached to a building wall that partitions an outdoor space and an indoor space, wherein

• the outside casing that includes a wall body, a thermal insulation material and a space forming member, the wall body being fitted in a wall communication hole and having an inside space in which the outdoor unit is capable of being disposed, the wall communication hole being formed in the building wall, the wall communication hole communicating between the outdoor space and the indoor space, the thermal insulation material disposed in the inside space of the wall body, the space forming member disposed between the wall body and the thermal insulation material,
• the inside space is opened to the outdoor space,
• the outdoor unit is disposed in the inside space of the outside casing, and
• the space forming member has a plurality of separation walls adjacent to each other in a depth direction from the outdoor space side toward the indoor space side, the separation walls defining a plurality of spaces adjacent to each other in the depth direction, between the wall body and the thermal insulation material.