An arrangement determining apparatus includes a center-of-gravity calculating processor that calculates a center of gravity of a three-dimensional model, a placement surface determining processor that determines a placement surface to attach and arranging supports thereon, a reference point setting processor that draws a perpendicular line from the center of gravity toward the placement surface and sets a reference point, a region dividing processor that divides the placement surface into a first region and a second region excluding the first region, and an arranging processor that attaches and arranges the supports on the placement surface so that the contact area per unit area between the first region and the supports in the first region is larger than the contact area per unit area between the second region and the supports in the second region.