PURPOSE: To carry out the blowing of cold temperature air into a car room from a side door with a simple structure by utilizing a reinforcing beam, in an air conditioner for an automobile door.

CONSTITUTION: A reinforcing beam, fixed in the longitudinal direction of a vehicle in a door panel of a front side door 1, is constituted of a pipe 10, also to connect its front side end part to an air supply pipe 13 from an air- conditioner provided in a vehicle front part, further to provide an air blow port 20, communicating with the pipe 10 through an air flow duct 15, in a door trim of the front side door 1.