A blood purification apparatus includes a blood circuit, a blood purifier, citric acid solution supply means and calcium solution supply means. The blood purification apparatus is configured to: estimate, based on an input of a target calcium ion concentration for a patient's blood, an amount of calcium loss throughout the blood circuit, including an amount of calcium removed by the blood purifier when blood having the target calcium ion concentration flows through the blood circuit； calculate a flow rate of the calcium solution to be supplied to the blood circuit based on the estimated amount of calcium loss； and supply the calcium solution to the blood circuit by the calcium solution supply means based on the calculated flow rate of the calcium solution.
