Provided is a multiplex water cutoff wall with a simple structure that can control water infiltration into an interior by way of being provided with multiple water cutoff walls and having a configuration to drain water having infiltrated between the water cutoff walls with a drainage means such as a pump. A plurality of water cutoff walls 1A, 1B, 1C, 1D are disposed in a multiplex configuration with gaps in the wall thickness direction. Drain pumps 4a, 4b, 4c are provided as the drainage means for discharging water having infiltrated between the water cutoff walls 1A, 1B, 1C, 1D to the outside. Water that has infiltrated between the water cutoff walls 1A and 1B when a rise in water level is caused outside the multiplex water cutoff wall during flooding is discharged to the outside of the multiplex water cutoff wall by the drain pump 4a. If necessary, the water cutoff wall can be arranged into a multiplex configuration with a third water cutoff wall 1C and a fourth water cutoff wall 1D, and water infiltrating therebetween is discharged with the drain pumps 4b, 4c. Thus, the level of infiltrating water is lower nearer the interior, and water flood damage can be prevented to a structure in the interior protected by the multiplex water cutoff wall.