A multiphase cellular automaton (CA) model was developed for 3D simulation of eutectic solidification. The weighted mean curvature method was used to calculate curvature of the 3D interface. To validate the model, simulations were performed for the formation of rod eutectic structure in succinonitrile-camphor binary alloy. The simulation results were compared with the Jackson-Hunt (JH) theory and previous experimental and phase field (PF) simulation studies. The relationship between the growth velocity of the solidification front and the rod spacing was in good agreement with that of JH theory and reported experimental results. In addition, the relationship between rod spacing and undercooling of the solidification front was very consistent with that of the JH theory and PF simulations. Rod splitting was observed when the rod spacing during unidirectional solidification was large, resulting in a rod spacing corresponding to smaller undercooling (i.e., stable growth condition from the JH theory) and the most stable hexagonal array of rods. From simulation of the model alloy, the morphology of the second solid phase changed from rod- to labyrinth-shaped when its volume fraction increased from 0.2 to 0.5. This is also consistent with the stability condition of rod morphology according to the JH theory (i.e., the volume fraction is 1/π or less). These results confirmed the validity of our model.