The invention is directed to the provision of a registration method and a placement assisting apparatus that can accurately register an object into a three-dimensional spatial database. More specifically, the invention provides a registration method for a location information tag, includes the steps of acquiring tag information of the location information tag, acquiring coordinate data that indicates scheduled placement information of the location information tag, acquiring positioning data that indicates placement location information of the location information tag, and registering the location information tag into a three-dimensional spatial database when an error between the coordinate data and the positioning data is within tolerance, and also provides a placement assisting apparatus for use in such a registration method.