The time-course characteristics of the amount of water absorption in vacuum-dried agar gels containing dimethyldioctadecylammonium chloride (DMDOAC), poly (vinyl acetate) emulsion (PVAc-E) and their mixtures was measured in order to investigate the water absorbency of food model systems. Scanning electron microscopy showed the network of the gel containing DMDOAC more indistinctly than that of the gel of agar alone. The clear network of the gel mixed with PVAc-E could be observed by the adsorption of PVAc in which was coherent in several pieces. The gel containing the mixture of DMDOAC and PVAc-E showed a network with adsorbed PVAc which was coherent in several pieces and seemed to be covered by DMDOAC. The water absorption process for each gel involved in common two steps, the first absorbing water at a high rate for about 120 min, reaching an inflection point at that time, and then absorbing water at a low rate, finally almost reaching saturation, without being influenced by the presence or concentration of the additives. The initial rate and saturation weight of water absorption for the gel of agar alone were 0.85 g/g·min and 21.8 g/g, respectively. The initial rate and saturation weight of water absorption for the gel including DMDOAC and the gel including the mixture of DMDOAC and PVAc-E showed exponential and logarithmic decreases with increasing concentration. The initial rate and saturation weight of water absorption for the gel including PVAc-E showed the maximum values at 0.1 wt% and minimum values at 1.0 wt%, the characteristic changing from the exponential decrease.