Abstract: A device for precisely placing instruments or implants in body organs with the aid of a targeting device (40) interacting with a computer tomograph, characterized in that the targeting device is arranged in the form of a navigation device (30) on a carrier (2) which is diplaceable on a substructure like a carriage which can be fixed in relation to the substructure and in that the navigation unit (30) comprises a retaining element for holding and guiding a targeting instrument, implant or other object. The navigation unit (30) can be displaced and/or rotated on one or several planes in relation to the carrier and the retaining element can be displaced and/or rotated on one or several planes in relation to the navigation unit (30), being reciprocally fixable in the adjusted position thereof.