The feasibility of a new reaction system with five components for the: simulated moving bed reactor (SMBR) was investigated. In this reaction, an oligosaccharide, lactosucrose (lactosylfructoside), was produced from sucrose and lactose using an enzyme, beta -fructofuranosidase from Arthrobacter. sP. K-l. Numerical simulation of the batch process showed that the performance of the reaction process is improved by product removal. The adsorption equilibrium of each component had been determined and SMBR experiments had been carried out. Lactosucrose and glucose were well separated in the SMBR and the lactosucrose yield was increased compared to the conventional batch reaction. The expected optimum lactosucrose yield was not attained due to strong product hydrolysis around the raffinate port.