To provide an elution control body in which fertilizer or the like is encapsulated in an elution control container allowing stable elution of a water-soluble material such as the fertilizer to water for a fixed period, and an elution control method of water-soluble materials using the elution control body.

In the elution control body, one or more water-soluble materials of fertilizers, nutrient sources and chemical agents are encapsulated in a container of an elution control membrane 1 composed of a porous membrane 2 including a cloth 3 made of nylon, polylactic acid or polyester and a porous membrane 2 covering the cloth 3, the porous membrane including at least one of polylactic acid, urethane resin and acrylic resin.