The invention relates to a furnace door opening-closing device for a flat-opening type quenching furnace. The furnace door opening-closing device comprises a base, a drive element and a performing device, wherein the base comprises a circular ring fixing ring, a fan-shaped connecting plate, a U-shaped connecting base, a center material penetrating ring, a rolling supporting ball, a centre connecting frame and an outer connecting column, wherein the drive element is fixed on the U-shaped connecting base; the performing device is arranged on the base; the performing device is connected with the drive element. The furnace door opening-closing device disclosed by the invention has the advantages of being reasonable in structural design, high in degree of automation, high in operation efficiency and the like, can realize automatic opening-closing of the furnace door, so that labor power is saved, safety performance is high, and injuries on operation staff can be avoided; synchronous movement in three directions is realized by utilizing one drive element, so that cost is saved, space utilization rate is high, movement effect is high and stability is high; the opening and closing of the furnace door is realized by adopting a flat-opening way, height dimension requirements on space are smaller, space utilization rate is high, and the defect that the conventional flip-cover type structure is greater in occupied space height dimension is overcome.