To have a function capable of discharging excessive pore water through a sheet pile when the ground is liquefied by earthquake or the like and to make it possible to prevent the lowering of water permeable capacity by the elapse of years.

A permeable material 20 of a three-dimensional net-like body of a plastic fine filament is provided and fixed to a recess section 12 in a recessed groove bottom of a concrete sheet pile 10 with a hat-like section and having a recessed groove 11 in the longitudinal direction. A small calibered pipe body having the opened upper end and the closed front end and having a large number of penetrating small holes in the middle part thereof is provided between the inside of a cross section of the permeable material or the surface of the recess section in the sheet pile and permeable material, and washing water is poured to prevent the pipe from being stopped up.