The physical properties of gel samples of varied hardness were examined and the intake quantity per mouthful investigated in healthy subjects for its effect on the swallowing characteristics, mastication method, and swallowing frequency. The samples were prepared from gelatin and an agar-derived gelling agent of varied molecular weight. The subjects, regardless of the quantity per mouthful of the sample, recognized the difference in such oral senses as stickiness and ease of swallowing. Gel samples, taken in small portions, that were soft, highly adhesive, and with a high tan δ value (viscosity element divided by elasticity element) were squashed between the tongue and palate by most of the subjects before swallowing, rather than masticated with the teeth. It was also found that the greater the adhesiveness, elasticity element G′ in the linear region, torque and viscosity element G″ in the non-linear region, the higher was the frequency of swallowing until the gel sample had been completely swallowed. The overall results demonstrate that humans alter the mastication method and frequency of swallowing until the food has been completely swallowed according to the physical properties of the food.