The effects of cooking pot material and heating conditions on the physical and chemical properties of rice gruel were studied. It was found difficult to adjust the heat input to rice gruel cooked in a yukihira nabe (earthen pot) when the temperature reached over 100°C at the bottom of a pot. Rice gruel cooked rapidly was harder and stickier than when cooked slowly, particularly when a yukihira nabe was used as the pot. Rice gruel cooked slowly had a large amount of reducing sugar, mainly consisting of glucose. Rice gruel that was too sticky was not easy to swallow and was disliked. Rice gruel cooked in an aluminum pot was preferred to that in a yukihira nabe, although the application of the heat retaining method to the latter type of pot was effective.