The present invention is to provide a protective agent against damage of biological tissue caused by near-infrared rays which is capable of blocking the near-infrared rays from reaching not only skin but also deeper tissue than the skin tissue, preventing damage of such tissue caused by the near-infrared rays and preventing pathogenesis and development of various disease and acceleration of aging both of which are caused by the near-infrared rays, and a product using the protective agent. The protective agent against damage of biological tissue caused by near-infrared rays comprises a near-infrared ray penetration blocker that absorbs, reflects or scatters the near-infrared rays to prevent the damage of skin and deeper tissue than the skin in a living body caused by exposure with the near-infrared rays.