It is located in Kawazu. The Kawazu-Nanadaru Loop Bridge is a double spiral bridge with a height of 45 m 148 ft, 80 m 260 ft in diameter, and a total length of 1,064 m 3,491 ft. From the direction of Shimoda/Kawazu Station, it goes uphill reversely, and from the direction of Izu/Amagi Tunnel, it goes downhill clockwise and loops 720 degrees twice.
The transference is one lane on each side, but the speed limit is limited to 40 km 25 mi per hour to intercept the danger of vehicles passing through this bridge, and overtaking is interdicted. In addition to cars and motorcycles, bicycles can also pass through the National Route. In 1981, the Kawazu-Nanadaru Loop Bridge was opened. In the same year, it won the Tanaka Award from the Japan Society of Civil Engineers.