PURPOSE: To produce calcium-containing vinegar having excellent properties to facilitate the taking of calcium of egg shell and make alkaline nature in the body and useful as a drink for health food or for cooking, etc., by immersing and dissolving egg shell in vinegar, thereby forming vinegar containing calcium of egg shell.

CONSTITUTION: Egg shell 1 is thoroughly washed with water and immersed in vinegar 2 filled in a vessel 3 for about 1 week to effect the complete dissolution of the egg shell 1 in the vinegar 2. The undissolved residual thin membrane of egg shell is scooped up and removed to obtain the objective calcium- containing vinegar having excellent properties to facilitate the taking of calcium of egg shell and make alkaline nature in the body, useful as a drink for health food or for cooking, etc., producible at a low cost, generating decreased amount of waste by the use of hitherto discarded egg shell calcium and making great contribution to health.