In order to improve mechanical and electric characteristics of carbon electrodes, they are impregnated with pitch. This impregnation operation can be accomplished at high efficiency by loading a plurality of electrodes on a specific pallet. However, when the carbon electrode-loaded pallet is dipped in an impregnation vessel, pitch adheres to the pallet, and if such pitch-adhering pallet loading fresh carbon electrodes thereon is introduced again into a pre-heating furnace prior to the impregnation operation, the pre-heating furnace is contaminated with pitch and there is a risk of a fire. In order to avoid this disadvantage, there is adopted a method in which different pallets are used for introducing carbon electrodes into the pre-heating furnace and for introducing them into the impregnation vessel, respectively. In this method, the operation of shifting carbon electrodes from one pallet to another pallet is necessary. In this invention, a specific shifting method is adopted for preventing carbon electrodes from being damaged or broken during the shifting operation.