To provide a field emission electron source capable of improving the electron emission characteristics, and to provide a manufacturing method thereof.

A field emission electron source 10 ((f) in Fig.1) includes a silicon substrate (semiconductor substrate) 1, a strong-field drift region 3 formed on a side of one of the surfaces of the silicon substrate 1, a lower electrode 2 formed on a side of other surface of the silicon substrate 1, and a surface electrode 4 formed on the strong-field drift region 3. The strong-field drift region 3 has a plurality of protrusions 31 formed at preset intervals of nanometers by etching the one of surfaces of the silicon substrate 1, lots of silicon micro-crystals (semiconductor micro-crystals) 33 of nanometers formed on the surface of each protrusion 31, and a silicon oxide film (insulating film) 34 formed on the surface of each silicon micro-crystal 33 and having a thickness smaller than the grain size of the silicon micro-crystal 33. Silicon micro-crystals 33 whose surface is covered with a silicon oxide film 34 are formed continuously along the surface of each protrusion 31.