PURPOSE: To eliminate the dispersion of trigger sensitivities and thus contrive to reduce the manufacturing cost by a method wherein the thyristor is formed in a structure wherein the positional slippage between a trigger part receiving the trigger signal for a thyristor element and the end part of a trigger signal guide which abuts to or contacts with the one adjacent thereto is not generated.

CONSTITUTION: The element 1 is so fixed on the first main surface of a metallic reinforcement disk before a cut 2a is worked that the photo receiving part 1a thereof is positioned nearly at the center of the first main surface of the metallic reinforcement disk 2. Over the whole periphery at the edge of the first main surface of the metallic reinforcement disk 2, the cut 2a having the fixed outer diameter is formed by mechanical working with a lathe, an NC milling machine, etc. wherein the normal of the main surface of the metallic reinforcement disk 2 which passes through the photo receiving part 1a so as not to reach from the first main surface to the second main surface. On the other hand, a positioning ring 11 is fixed on the step wall surface of the cut 5a of an insulation cylinder 5. The cut 2a of the metallic reinforcement disk 2 is fitted into the positioning ring 11, and then the second electrode body 4 is air-tightly fixed on the end surface to the side of the cut 5a of the insulation cylinder 5 by using the second flange 7 by abutting and contacting the element 1 on the end surface of the first electrode body 3.