To improved current carrying properties of an electron emitting member, and to increase the area of an electron emitting surface in the electron emitting member.

A cathode 53 has a power supply member 58 formed of tungsten, and an electron emitting member 59 which is a wire formed of tantalum. The electron emitting member 59 is wound around the power supply member 58 so that the peripheral surfaces of adjoining electron emitting members 59 are brought into contact with each other. In this electron emitting member 59, since not only a current flows along a winding direction, but also flows along the progressing direction of winding, current carrying properties of the electron emitting member 59 is improved. In addition, since the exposed peripheral surface S2 functions as an electron emitting surface S2 in the wound electron emitting member 59, and the electron emitting member 59 is the wire, the electron emitting surface S2 is formed into a wavelike curved surface on which uneven parts are continuous, and the area of the electron emitting surface S2 increases.