A field emission electron source includes a carbon nanotube micro-tip structure. The carbon nanotube micro-tip structure includes an insulating substrate and a patterned carbon nanotube film structure. The insulating substrate includes a surface. The surface includes an edge. The patterned carbon nanotube film structure is partially arranged on the surface of the insulating substrate. The patterned carbon nanotube film structure includes two strip-shaped arms joined at one end to form a tip portion protruded from the edge of the surface of the insulating substrate and suspended. Each of the two strip-shaped arms includes a plurality of carbon nanotubes parallel to the surface of the insulating substrate. A field emission device is also disclosed.