An efficient process suitable for a large-scale production of fucose from the seaweed of Undaria pinnatifida was developed in this study. The developed process consisted of a hydrolysis, a series of pretreatment processing for decolorization and deionization, and a final-stage purification using a well-designed simulated-moving bed (SMB) process. First, the optimal acid concentration and reaction time for the seaweed hydrolysis were investigated. The hydrolysate resulting from such investigation was then used to determine the optimal operating conditions for the pretreatment step consisting of an activated-carbon treatment, an electrodialysis, and an ion exchange processing, which were performed to accomplish decolorization and deionization. On the basis of the optimal conditions that were obtained from the preceding experiments, a series of hydrolysis and pretreatment operations were carried out to secure a sufficiently large amount of decolorized and deionized hydrolysate. This was then moved on to the final purification step based on the use of the SMB process, which was designed such that the detailed recovery of fucose with a very high purity in a continuous mode could be ensured. The results showed that the purity of fucose, which reached 15.4% after the completion of the pretreatment processing, was markedly increased to nearly 100% through the SMB processing. It was also confirmed that the overall loss of fucose amounted to 22.9%, and most of the fucose loss occurred during the electrodialysis and ion-exchange procedures whereas there was almost no loss during the SMB processing.