Abstract: A calcium containing composition was obtained by baking sea urchin shells. This calcium containing composition gives superior oral bioavailability, has better appearance and taste, contains low impurity, and provides high yield. Therefore, this sea urchin shell derived calcium containing composition is useful in the treatment and prophylaxis of various diseases which require calcium supplementation such as hypocalcemia, osteoporosis, renal osteodystrophy, and so forth. Also, it is suitable to combining into health food and feed for the purpose of calcium supply.