The Rarumanai Waterfall is one of the three waterfalls in Rarumanai Natural Park. It is on a tributary river of the Rarumanai River and directly flows down the drop of 20 m into the main river. The waterfall is divided into two parts, which are different in flow. Interestingly, a bridge of the promenade crosses just above the point that changes the flow. From the bridge, the upper part of the waterfall, which smoothly flows down on the platy surface of the river bed, can be seen. It looks like silk thread curving gently. The lower part cannot be seen from the bridge; however, the splashing flow of water, which runs down the drop of 7 m in two directions, can be viewed from nearby “Takimi Hiroba (waterfall viewing space)”. As there is a cluster of Japanese maple trees in the area around the base of the waterfall, visitors can enjoy the beautiful contrast of crimson foliage and the waterfall falling gently in the deep green valley.