To provide a bus duct support structure which allows a bus duct to be built even in small installation space and can support it.

The bus duct support structure supports bus ducts 100 in which insulator-covered conductors 600 are covered with housings 30 and which are arranged side by side roughly vertically in a structure, by supporters, such as floor supporters 400, which are installed on both sides of each bus duct 100, being fixed on a floor 300. A part of the housing 30 on both sides in the thickness direction of the bus duct 100 is contracted to constitute a reduced part 102, and the supporter is attached to the reduced part 102 of the housing 30.