An automatic analyzing apparatus has an analysis section including an immunity analysis unit and a biochemical componential analysis unit. A sample rack which has undergone the immunity componential analysis is horizontally fed by a rack feeding mechanism from a position confronting the inlet of a rack stationing section to a position near the outlet of the rack stationing section, so that the sample rack is directly moved to a return line, while skipping over the rack stationing section, so as to be efficiently returned to the analysis section and subjected to a subsequent biochemical analysis. A sample rack that needs reexamination by an identical analysis unit is also returned in the same efficient way.