The semiconductor device includes an interconnect having a width of 0.1 μm or less and formed in an insulating layer constituted of a low relative dielectric constant film having a relative dielectric constant of 3.0 or lower, a via having a diameter of 0.1 μm or less and connected to the interconnect, and a dummy metal provided in the insulating layer. The dummy metal is located close to an end portion of the interconnect along an extension thereof, and the dummy metal and the interconnect are spaced by a distance of 0.3 μm or less.