A heavy construction equipment supporting device is disclosed. According to one embodiment of the present invention, the heavy construction equipment supporting device comprises: a support unit maintaining a fixed state with the outside of a steel frame column while being inserted into an upper portion of the steel frame column installed in a slab of a building under construction in a nuclear power plant; and a mounting unit mounted in the upper portion of the steel frame column and wherein heavy construction equipment is installed on an upper side of the support unit.
