An apparatus is configured including an information obtaining unit that extracts information on plural parts' attributes, locations, and adjoining relations with other parts; a unit that sorts parts by part type and detects a distinctive shape from 3D CAD model; a unit that represents adjoining relations between parts in an assembly graph; a unit that creates disassembling directions and a disassembling sequence based on the assembly graph and, by reversing them, derives an assembling sequence and assembling directions; a unit that computes an index indicating a quality of easiness of assembling a part by subtracting the sum of deficiency points per part from a reference score; a unit that creates virtual worker positions, postures, and viewpoints according to assembling sequence and evaluates workability; and a unit that computes an evaluation value per part by the index of easiness of assembling the part and a total evaluation value of assembly workability.