A semiconductor device manufacturing method includes forming fins in first and second regions defined on a substrate. The fins include first fin, second fin, third fin, and fourth fin. A dielectric layer is formed over fins and a work function adjustment layer is formed over dielectric layer. A hard mask is formed covering third and fourth fins. A first conductive material layer is formed over first fin and not over second fin. A second conductive material layer is formed over first and second fins. A first metal gate electrode fill material is formed over first and second fins. The hard mask covering third and fourth fins is removed. A third conductive material layer is formed over third fin and not over fourth fin. A fourth conductive material layer is formed over third and fourth fins, and a second metal gate electrode fill material is formed over third and fourth fins.