In a vehicle air conditioner, a first warm air diversion passage is a tunnel-shaped passage that is provided near a first side air outlet and takes in warm air and causes the air to flow without mixing with cool air. A second warm air diversion passage is a passage inside a tunnel that is provided near a second side air outlet and takes in warm air and causes the air to flow without mixing with cool air. A diversion passage section includes an in-tunnel guide wall that directs the warm air flowing through the first warm air diversion passage toward the first side air outlet, and an in-tunnel guide wall that directs the warm air flowing through the second warm air diversion passage toward the second side air outlet.