Provided is a method for manufacturing a silicon nanowire array comprising the steps of: positioning plastic particles separated apart from one another in a uniform random pattern on a silicon substrate; forming a catalyst layer between the plastic particles; removing the plastic particles; vertically etching portions of the silicon substrate that contact the catalyst layer; and removing the catalyst layer. The present invention provides a simple and cost-effective process, enables mass-production through large surface area processing, enables the manufacture of nanowire even at a site having limited resources, and enables the structures of nanowire to be individually controlled.