Abstract: A semiconductor circuit structure including a semiconductor substrate portion and at least one region provided on one main surface thereof insulatedly isolated from other regions provided on the same surface, by burying means made of an oxide film, the burying means including a bottom flat portion and at least one side wall portion provided at least in the vicinity of an edge portion of and integrally formed with the bottom flat portion, thereby a semiconductor circuit structure provided with a plurality of insulatedly isolated regions on a main surface thereof and having a high withstand voltage can be obtained in a short production process.