The three-station fully automatic nailing case erector can simultaneously erect cartons of three different sizes. The fully automatic servo-driven case erector is equipped with a multi-station carton storage system, allowing multiple magazine units to hold cartons of varying dimensions and enabling seamless automatic switching between sizes. The fully automatic case erector automatically nails the bottom flaps of the carton during setup—eliminating the need for manual adjustments and effectively resolving the challenges associated with frequent carton size changeovers.