PURPOSE: To increasing the operation speed of static induction transistors, to raise the source range provided under drain range and to reduce the distance between said both ranges.

CONSTITUTION: First conductive range 30 such as n-type one for example is formed on a semiconductor substrate 27, and n-1-range 22 thereon. p-type range 23 is provided in said range 22 so as to surround the n+-range 24 and the portion for serving as channel of said range 22. Further, the range having a lower specific resistance than said range 22 and protrudent into said range 22 is provided in the range directly under said range 24. Thereby, the SIT portion of a static induction transistor is formed of said range 30 as source, the range surrounded by said range 23 of said range 22 as channel, said range 23 as gate and said range 24 as drain. The operation speed of said SIT can be raised without increasing the capacity between drain and gate by reducing the distance between said source range 30 and drain range 24 and the resistance between drain and gate.