An object is to provide a holding fixture fixing apparatus which can ensure positioning accuracy and shape accuracy of a moving holding fixture, thus allowing an aircraft panel to be assembled with high accuracy. A holding fixture fixing apparatus includes a plurality of fixing units configured to support and fix a holding fixture, which holds a fuselage panel having a curved shape in cross section, from a lower surface of the holding fixture, the fixing units being provided on an installation surface, wherein the plurality of fixing units are provided corresponding to at least four corners of the lower surface of the holding fixture.