An electric discharge inducing method along curved discharge paths in a vacuum using a laser beam has been found. The discharge path in the present method is considered to be controlled by the passage of thermoelectrons along the electric field. Therefore, the path can trace not only a straight line but also curved lines. The thermoelectrons are emitted from a metal plasma, which is generated by a laser beam irradiation onto a metal surface (an electrode). Based on the present inducing principle, the discharge can be induced from an anode even to the back surface of the cathode through a hole in the cathode.