The invention relates to a positioning and immobilization device for positioning and immobilizing a mandibular or maxillary surgical guide on a patient, which guide is adapted to preparing for and to fitting at least one dental implant and is provided with a link slab member designed to extend outside the oral cavity when the surgical guide is placed in register with the patient's mandible or maxilla, said positioning and immobilization device being characterized in that it comprises a body that has bearing face for bearing against the outside of the head of the patient, and a fastener designed to co-operate with the link slab member of the surgical guide.