To improve an execution property by covering the surface of a stainless coil spring with a knitted wire net made of a fine wire of the same material, and burying it in a drainage pavement layer.

The surface of a coil spring is covered with a knitted cylindrical wire net 2 to form a seepage water drain member. The spring 1 is made of stainless steel or aluminum which is excellent in rust resistance, resilience and depression resistance and can sufficiently withstand a vehicle load. The wire net 2 is formed with a fine wire made of the same material as that of the spring 1 or a twisted thread of glass fibers and prevents electric corrosion caused by the contact of different metals. A drainage surface layer is provided on a base layer via a waterproof layer at the time of execution, for example, the seepage water drain member is buried in the drainage surface layer, and the rain water stopped by the waterproof layer is drained to a catch basin by the seepage water drain member. The expansion/shrinkage and meandering of the coil spring 1 by the rolling compaction pressure at the time of pavement material execution can be prevented, pavement material fine grains are prevented from infiltrating into the seepage water drain member, and a good drainage function can be maintained.