To provide a temporary cofferdam construction method capable of temporarily coffering the broken position of a river levee in an emergency by a simple construction method.

This construction method temporarily coffers the broken position of a river levee in an emergency. Multiple unit blocks 1 each formed with a group of steel pipes 2 are installed at the broken position of a river levee G, inner piles 5 inserted into the steel pipes 2 are driven into the ground, then water barrier plates 4 are dropped between the steel pipes 2. The unit block 1 is provided with recesses 3 in the vertical direction on the side faces of the hollow steel pipes 2, the water barrier plates 4 are fitted to the recesses 3 in advance, the inner piles 5 are inserted into the steel pipes 2, and the steel pipes 2 are fixed together by ties 6.