Saprolegnia spp., common aquatic fungi, are known as one of the appropriate material to observe the reproductive process in its life cycle. The aim of the present study is to modify culturing method of Saprolegnia sp. We prepared culture media containing various concentration of the Cannabis extract solidified by agar. The hyphae of Saprolegnia sp. were cultured in sterilized water with small pieces of the agar media. As the result, many zoosporangia and archegonia were observed under the light microscope. In comparison with the ordinary culturing method using whole cotyledon of Cannabis, the colonies of Saprolegnia sp. obtained by this modified method were suitable to observe various stage of life cycle. The nutritional conditions in culturing are able to be controlled by this method. Therefore, it will be used as the practical method in the biology class.