An intraoral three-dimensional measuring method, comprising: acquiring, with a handy scanner, wide range three-dimensional measurement information on a three-dimensional shape measured on a wide range in a desirable measurement range in an intraoral space; acquiring, with the handy scanner, a plurality of pieces of narrow range three-dimensional measurement information each on a three-dimensional shape measured on a narrow range narrower than the wide range in the measurement range; and locating, with a controller, the plurality of pieces of narrow range three-dimensional measurement information based on the wide range three-dimensional measurement information by use of, as a synthesis reference, intra-measurement range position information common to the wide range three-dimensional measurement information and each of the plurality of pieces of narrow range three-dimensional measurement information, and creating synthetic three-dimensional information on the measurement range.