Electron gun and electron beam device

An electron gun comprising:

• an emitter;
• an electron gun electrode;
• a short-circuiting mechanism for setting the emitter and the electron gun electrode at the same potential;
• and
• an electron gun chamber in which a terminal plate is provided, the terminal plate having a terminal that is electrically connected to the emitter and a terminal that is electrically connected to the electron gun electrode,
• wherein the short-circuiting mechanism comprises:
• a first switch member provided with a first switch electrode that is connected to the emitter and a second switch electrode that is connected to the electron gun electrode;
• a second switch member provided with a third switch electrode;
• and
• a drive unit that operates at least one of the first switch member and the second switch member to switch between a state in which the first switch electrode and the second switch electrode are in contact with the third switch electrode and a state in which the first switch electrode and the second switch electrode are separated from the third switch electrode,
• wherein the short-circuiting mechanism is located on the terminal plate, and
• wherein the drive unit comprises a nut, a screw shaft that is screwed to the nut, and a motor that rotates the screw shaft, and the motor rotates the screw shaft to push downward and rotate the first switch member.