PURPOSE: To raise the durability of a rubber dam by a method in which two double rubber strips are bonded the selvages with each other over the whole longitudinal direction on their one sides to form a rubber dam body, and the selvages of opened side of the rubber dam body is fixed to the bad and bank of a river by using fitting metals.

CONSTITUTION: The selvages of two doubled rubber strips 3 and 4 are bonded with each other over whole longitudinal direction on their one sides to form a rubber dam body 1. Then, the opened side of the rubber dam body 1 is positioned toward the upstream side, the hole provided in the selvages of opened side of the rubber dam body is connected with an another bolt 6 buried in the river bed 5, and a push plate 7 is contacted with the selvages of the rubber dam body and fixed airtightly by nuts 8. Then to fix the dam body to the bank of the rever, both ends of the rubber dam body 1 are slantly cut off toward the downstream side, and the opened sides are airtightly attached by means of the anchor bolt 6, the push plate 7, and nuts 8 as in the case of the river bed 5.