[Object]To provide a substrate processing method capable of forming a concavo-convex structure on a substrate surface while reducing the number of processes.[Solving Means] In a substrate processing method according to the present invention, particles are dispersed on a surface of a substrate, and a concavo-convex structure is formed on the surface of the substrate by etching the surface of the substrate with the particles as a mask and the mask is simultaneously removed by the etching. According to this method, a process of removing the mask from the substrate surface after the concavo-convex structure is formed becomes unnecessary. Accordingly, since the number of processes necessary to form the concavo-convex structure on the substrate surface is largely reduced, it becomes possible to greatly improve productivity.