To provide a method for producing a calcium carbonate block for medical use which is useful as a bone substitute or a bone substitute raw material needed in medical care, which is a method for producing a calcium carbonate block that satisfies the following desired properties: 1) the calcium carbonate block has excellent mechanical strength； 2) the calcium carbonate block can be produced by a simplified production method； 3) the calcium carbonate block contains no impurity； and 4) the calcium carbonate block has high reactivity.A method for producing a calcium carbonate block, comprising a step of shaping a water-containing calcium hydroxide block and a carbonation step of immersing the calcium hydroxide block in a carbonate ion-containing aqueous solution.
