In a design support apparatus, a storage unit stores location data of an assembly including a first member long and flexible and a second member connected to the first member and having a larger cross-sectional shape than that of the first member within a product, and respective positions of installed objects. A geometric center calculation unit virtually extends straight lines from a point on a route along which the first member passes, radially in directions normal to a tangential direction of the route, virtually positions points where the straight lines come into contact with the installed objects, and calculates a geometric center from the positioned points. A route change unit changes the route such that the first member passes the calculated geometric center. A verification unit verifies whether or not the assembly interferes with any of the installed objects during passage of the first member along the changed route.