PURPOSE: Calcium is provided to be easily absorbed in a body when eating calcium gruel by adding ionized calcium in rice for gruel and liquid for gruel to easily dissolve calcium in an aqueous state. CONSTITUTION: Calcium gruel comprises rice for gruel, liquid for gruel, and ionized calcium. The ionized calcium is prepared by using shells. The shells include oyster shells. The calcium gruel further includes a supplementary material including at least one selected from the group consisting of vegetable, mushroom, meat, seafood, and seaweed； and a seasoning including at least one selected from the group consisting of salt, pepper, sesame oil, and curry. The calcium gruel is prepared by adding the ionized calcium in the rice for gruel and the liquid for gruel. The ionized calcium is added to at least one of the rice for gruel and the liquid for gruel before heating the rice for gruel and the liquid for gruel. 0.1 to 3g of the ionized calcium is added to 1L of the liquid for gruel. A manufacturing method of the ionized calcium comprises the steps of: pre-pulverizing shells； and calcinating the pulverized shells by heating to a temperature of 1000>；= or higher. The calcinating step is performed for 20 to 30 hours. The calcinating step is performed at a temperature of 1200 to 1600>；=. [Reference numerals] (ST10) Step of preparing raw materials for gruel； (ST20) Step of heating and boiling the raw materials for gruel； (ST30) Step of adding ionized calcium；본 발명은 칼슘 죽 및 이의 제조 방법에 관한 것이다. 본 발명의 실시예에 따른 칼슘 죽은, 죽용 쌀, 죽용 액체 및 이온화 칼슘을 포함한다. 본 발명의 실시예에 따른 칼슘 죽의 제조 방법에서는, 죽용 쌀 및 죽용 액체에 이온화 칼슘을 첨가하여 칼슘 죽을 제조한다.
