An electron emitter includes a guard electrode 13 on the outer circumferential side of a carbon film structure 10 which is formed on a substrate 7 by plasma CVD method. This guard electrode 13 includes a curved surface portion (a curved surface portion that curves from top toward a side opposite to the film-forming direction) 13a convex in a film-forming direction of the carbon film structure 10. A curvature radius R1 of an outer-circumferential-side portion of the curved surface portion 13a is larger than or equal to a curvature radius R2 of a carbon-film-structure-side portion of the curved surface portion 13a.