To provide a field emission electron source consisting of conical projections of Cu2O with high performance and its manufacturing method.

The field emission type electron source uses Cu2O conical projections. It is desirable that the conical projections have a curvature radius of 15-200 nm and an opening angle of 5-60 deg of the top end of the projections, and it is more desirable that the curvature radius is 20-70 nm and opening angle is 10-30 deg for the projection top end. Furthermore, the ratio of the length l and curvature radius of the conical projection is l/15. In the manufacturing method of the field emission electron source, Ar ion is irradiated from perpendicular direction under low vacuum on the top end of the tip of the Cu wire which is applied preliminary oxidation, and the Cu2O conical projections are formed on the top end of the tip. As the Cu wire, one is used which includes a mechanical polishing or electrolytic polishing applied beforehand.