A furniture design support system comprises a computer system. The computer system comprises an HD unit, which stores a furniture design support program and data representing the basic forms of units and parts. An operator defines a size, a finishing color, a material (the kind of wood), etc. with respect to the unit to be used for furniture to be designed on the basis of the desires of a customer, and also defines a finishing color, a material, etc. with respect to the part (a drawer, a door leaf, etc.) (step 33). Completed furniture is displayed on a display screen by assembling the unit and the part on the display screen. An HD stores design data related to the completed furniture (step 34). The appearance of the completed furniture is displayed on the display screen on the basis of the design data, and a design drawing is outputted from a printer (step 35).