A semiconductor device manufacturing method includes: forming a first well of the first conductivity type in a substrate; forming a second well of the first conductivity type in a first region of the substrate; forming a third well of the second conductivity type underneath the second well in the first region of the substrate in a position overlapping with the first well located underneath the second well in the first region of the substrate; forming a fourth well, that surrounds the second well and has the second conductivity type, in the first region of the substrate; forming a fifth well of the first conductivity type above the first well in the second region of the substrate; and forming a sixth well of the second conductivity type above the first well in the second region of the substrate.