PURPOSE: To construct a railroad or an exclusive vehicle road by utilizing a river reservation without impairing the natural sight, and without blocking the water flow.

CONSTITUTION: At the underground part of a river, reservation 12a, two lines of underground spaces 14 and 14a for the ups and the downs are constructed, and the underground spaces 14 and 14a are partitioned into the first, the second, the third, the fourth, and the fifth partition passages 22a, 22b, 22c, 22d, and 22d in order from the upper side. The first partition passages 22a are, used for the housing spaces of cables of such a communication cable and a power cable, while exclusive vehicle roads 18 and 18a are constructed in the second partition passages 22b. Railroads 16 and 16a are laid in the third partition passages 22c, the fourth partition passages 22d are used for common grooves, and the fifth partition passages are used for drainage ditches.