The concentration phenomena during freezing and thawing were investigated to study the feasibility as an industrial concentration operation. A dye solution was employed as a model binary eutectic solution, and the solution was directionally frozen with conventional cooling plate freezer. It was found that a certain amount of ice layer was appeared just after the ice nucleation from supercooled solution depending on the supercooling degree of the samples, and, the concentrations in this layers were found to be same as the original solution. After the subsequent ice crystal growth, the solute was accumulated onto the top of the freezing sample, as a consequence, the concentration of the top 30 % of frozen matrix was approximately 1.2 times higher than original solution. However, the concentration of the melting solution was around 1.5 ~ 2.0 times higher than the original solution at the beginning half of thawing, and, this trend depended on the freezing conditions and the thawing conditions. It was suggested that the concentration phenomena during thawing would be governed by the melting droplet growth rate at the melting interface and by the diffusion rate of solute from eutectic phases to the droplet. The presentation will show the currently obtained experimental results of this concentration phenomenon of the freeze-thawing, and the feasibility as an industrial unit operation will be discussed.