A semiconductor integrated circuit comprising: - a plurality of circuit cells; - a plurality of groups of groups of power lines arranged in strip shapes; - a power switch cell; - a first, a second, a third and a fourth group of branch lines (BL2-1-BL2-4) connected to said power switch cell, wherein the semiconductor integrated circuit is characterised in that said first and second groups of branch lines are adjacent to each other and are configured to supply power to first ones of said circuit cells and in that said third and fourth groups of branch lines are adjacent to each other and are configured to supply power to second ones of said circuit cells; wherein: - said first and second group of branch lines (BL2-1, BL2-2) share a first branch line (VSSB); - said third and fourth group of branch lines (BL2-3, BL2-4) share a second branch line (VSSB); - said first and third group of branch lines (BL2-1, BL2-3) extend in opposite directions to each other across said power switch cell; - said second and fourth group of branch lines (BL2-2, BL2-4) extend in opposite directions to each other across said power switch cell; - said switch cell comprises: ∘ a first interconnect line connected to said first and second branch lines (VSSB); ∘ a second interconnect line connected to a branch line branching from said power line; and ∘ a switch circuit connected between said first and second interconnect lines (L211, L212) and turning on or off in accordance with said control signal. - a plurality of circuit cells; - a plurality of groups of groups of power lines arranged in strip shapes; - a power switch cell; - a first, a second, a third and a fourth group of branch lines (BL2-1-BL2-4) connected to said power switch cell, wherein the semiconductor integrated circuit is characterised in that said first and second groups of branch lines are adjacent to each other and are configured to supply power to first ones of said circuit cells and in that said third and fourth groups of branch lines are adjacent to each other and are configured to supply power to second ones of said circuit cells; - said first and second group of branch lines (BL2-1, BL2-2) share a first branch line (VSSB); - said third and fourth group of branch lines (BL2-3, BL2-4) share a second branch line (VSSB); - said first and third group of branch lines (BL2-1, BL2-3) extend in opposite directions to each other across said power switch cell; - said second and fourth group of branch lines (BL2-2, BL2-4) extend in opposite directions to each other across said power switch cell; - said switch cell comprises: ∘ a first interconnect line connected to said first and second branch lines (VSSB); ∘ a second interconnect line connected to a branch line branching from said power line; and ∘ a switch circuit connected between said first and second interconnect lines (L211, L212) and turning on or off in accordance with said control signal. ∘ a first interconnect line connected to said first and second branch lines (VSSB); ∘ a second interconnect line connected to a branch line branching from said power line; and ∘ a switch circuit connected between said first and second interconnect lines (L211, L212) and turning on or off in accordance with said control signal.