A semiconductor device includes an internal circuit and a power mesh configured to transmit an operating voltage to the internal circuit. The power mesh includes first power lines extending in a first direction and arranged in a second direction intersecting with the first direction, when viewed from a top; second power lines sharing lanes with the first power lines and at least partially overlapping with the first power lines in the second direction; first power straps extending in the second direction and coupled to the first power lines; and second power straps extending in the second direction and coupled to the second power lines. Each of the first and second power lines may have a width of the same size as a width of each lane in sections where they do not overlap, and may have a width of a size smaller than the width of each lane in sections where they overlap.