An assembly information management apparatus includes a detection means for detecting an update of a selected part selected from a group of parts constituting any assembly information in the set, a first calculation means for calculating outline shape data of the selected part after being updated from the selected part detected by the detection means, an identification means for identifying a common assembly information group sharing the selected part from the set, a second calculation means for calculating outline shape data of common assembly information for each piece of common assembly information identified by the identification means based on outline shape data of remaining parts after excluding the selected part constituting the common assembly information and outline shape data of the selected part after being updated calculated by the first calculation means, and an association means for associating each piece of the common assembly information with outline shape data.