PURPOSE: To obtain the characteristics of variable capacitance having excellent linearity and low series resistance, by forming layers having the same conductivity type stepwise on a semiconductor substrate, forming a layer having the reverse conductivity type, and providing a structure whose conductivity becomes higher as said layers having the same conductivity approach the conductor layer at the surface from the bulk of the semiconductor substrate.

CONSTITUTION: An N-type diffused layer 9 is formed between an N-type epitaxial growing layer 2 and an N-type diffused layer 3. Thus, the layers having the same conductivity type are formed stepwise in stages. In this structure, the impurity concentration region of the N-type diffused layer having a wide field of view is formed on the side of the N-type epitaxial growing layer 2 in comparison with a conventional element structure. The total amount becomes larger than in the conventional structure. The series resistance at this part is decreased. Therefore, when this capacitor is used, e.g., in an electronic tuning circuit for a tuner and the like, the range of a variable voltage is wide, and tracking errors can be reduced. Since the series resistors are implemented, a performance index Q of a circuit including the variable semiconductor capacitor can be made high.