1. A design workflow construction apparatus for supporting design of an object to be designed constituted by a plurality of entity design elements by individually designing the plurality of entity design elements, wherein: in design of the object to be designed, input variables, design variables, and intermediate variables are used, the input variables being given in advance when the object to be designed is designed, the design variables being determined when the plurality of entity design elements are designed, and the intermediate variables being uniquely determined when the input variables and the design variables are determined, in design of each of the plurality of entity design elements, at least part of a variable group constituted by the input variables, the design variables, and the intermediate variables is used as a design condition, and intermediate variables that are not used as the design condition are determined as a design result, and the design workflow construction apparatus comprises: specifying information acquisition means for acquiring entity design element specifying information for specifying the plurality of entity design elements and important design variable specifying information for specifying, as important design variables, part or all of the design variables; and design order determining means for determining an order of designing the plurality of entity design elements and an order of determining the important design variables so as to reduce the number of combinations of entity design elements in which an intermediate variable determined as a design condition of a first entity design element becomes an intermediate variable obtained as a design result of a second entity design element that is designed later than the first entity design element.