PROBLEM TO BE SOLVED: To provide calcium, i.e. natural calcium in a nanosized state from a calcium-containing material originated from an organism.SOLUTION: The method for providing a natural calcium-solubilized solution includes subjecting water containing rock and an organic acid to vibration treatment preferably ultrasound-radiation treatment. As a result, the natural calcium-solubilized solution containing the natural calcium in a solution state by being stabilized can be provided. Especially, pulverized granite is preferable as the rock, and citric acid is preferable as the organic acid. The radiation time of the ultrasound-radiating treatment is preferably about ≥1 h, especially 5-10 h.
