An object is to provide an electron emitting cathode achieving high luminance, low energy dispersion, and long life. It is therefore an object to provide a diamond electron emitting cathode graspable on a sufficiently stable basis, sharpened at the tip, and improved in electric field intensity. A diamond electron emitting cathode 110 according to the present invention is partitioned into at least three regions, i.e., a front end region 203 intended for electron emission at a tip of columnar shape, a rear end region 201 intended for grasping opposite in the longitudinal direction, and a thinned intermediate region 202, a cross-sectional area of the rear end region is not less than 0.2 mm2, the tip of the front end region is sharpened, and a maximum cross-sectional area of the thinned intermediate region is not more than 0.1 mm2.