An air supply apparatus is between an air mattress and a foundation including transverse openings. The air supply apparatus elevates the air mattress and includes a transverse air bladder; a connection assembly including a first line having one end connected to an outlet of an air compressor and communicating therewith, a female connector at the other end of the first line, a check valve in the female connector and communicating with the first line, a second line having the other end coupled to the air bladder by passing through the transverse openings so as to communicate with the air bladder, and a male connector at one end of the second line and including a port wherein the female connector is inserted into the male connector to connect the check valve and the port together; and straps on a top of the foundation for fastening the air bladder thereon.