This study aims to investigate the melting behavior of the ice plate with a calcium chloride solution in a rectangular container. When the ice layer is melted by the calcium chloride solution, the ice layer melts while absorbing the latent heat of fusion, and both the concentration difference and the temperature difference occur in the aqueous solution. Consequently, it occurs double diffusive convection, the melting behavior is expected to be complex. In this study, the melting behaviors in the case where the initial temperature of the ice layer and the aqueous solution is uniform, have been examined by three-dimensional numerical calculation. The effects of double diffusive convection on both the temperature and the concentration profiles in a rectangular container have been revealed from the present investigation.