Study on saving gear for the trawl fishery will play an important role in saving immature fish. Model experiments were conducted with the intent to improve and develop a new trawl net with a bottom curtain. The paper published by LARSSON gave important clues for designing the bottom curtain and the experiments were conducted in a circulating experimental tank. This paper deals with the behavior of a ground trawl net having a bottom curtain as a preliminary step to gear designing. Results of the experiments were obtained by means of visual observation and numerous photographs taken through the glass wall of the tank. It was found that the net height increased by means of attaching the bottom curtain, but slack in the lower part of the bottom curtain was also observed.