We developed a non-woven polypropylene (PP) SERS substrate using melt-brown PP nonwoven fabric as the base material, which enabled mass production. Ag nanoparticles were physically modified on the PP nonwoven fibers with a particle size of 30 nm by the reduction reaction of the Ag nitrate solution. The fabricated SERS substrate achieved detection of 4-aminothiophenol (4-ATP) within the range of 10^-7 to 10^-3 M. This sensor response was higher than that of a previously developed electroless Ag-plated PP SERS substrate. The results of storage at room temperature and under dark conditions for two weeks showed no decrease in response, but the variability of response increased to CV=23.3%, indicating that the storage method needs to be considered. Thus, the fabricated SERS substrates using melt-brown PP nonwoven fabric are sensitive, easy to fabricate, low cost, and environmentally friendly.