In atomic Fermi gases, the pairing character changes from BCS-like to BEC-like when decreasing the threshold energy of the Feshbach resonance. With this crossover, the system enters a strong-coupling regime through the population enhancement of diatom molecules, i.e., tightly bound Cooper pair, and the vortex structure shows much different features in contrast to the well-known core structure in BCS superfluid. In this paper, we study the structure of a single quantized vortex by numerically solving the generalized Bogoliubov–de Gennes equation derived from the boson–fermion model and clarify how the vortex structure changes with the crossover from BCS to BEC. As a result of numerical calculations, we find that the presence of the diatom molecular condensate enhances the matter density depletion inside the vortex core in the crossover regime and the Caroli–de Gennes–Matricon (CdGM) quasi-particle branch almost diminishes in BEC regime.