The microwave antenna includes a substrate, an antenna element supported on a surface of the substrate, and a power feeding electrode connected to the antenna element. The antenna element includes a carbon nanotube structure constituting a network structure having plural carbon nanotubes electrically connected to each other. The process for producing the microwave antenna includes applying plural carbon nanotubes each having a functional group to a surface of the substrate and crosslinking the functional groups with a chemical bond to form a crosslinked part, so as to form the carbon nanotube structure.