A mineral absorption promoting agent containing oligouronic acid, e. g. oligogalacturonic acid or oligomannuronic acid �degree of polymerization (n)=1 to 9! is described. Since this oligouronic acid �polymerization degree (n)=1 to 9! forms a complex with mineral, it promotes absorption of minerals into living organisms by simply adding it to foods, drinks or pharmacentical compositions for oral use. Since the agent has no problem with safety, the agent is suitable for repeated eating, drinking or taking, and the agent is very effective.