Proposed is a method for automatically replacing an electrode reel of a secondary battery which includes a reel holder mounting step, an adhesive providing step, a production reel outer diameter detection step, a production reel moving step, a standby reel supply step, and a material connection step of connecting an electrode material of the production reel of the bobbin buffer part and an electrode material of the standby reel to each other by using the adhesive, and cutting a remaining electrode material of the production reel.