In order to simply produce a microstructured body in which metal particles are arranged so as to be fixed to depressions of a metal substrate having at a surface a structure of protrusions and the depressions, a process for producing the microstructured body includes the steps of: (A) preparing a metal substrate 11 with a surface having a structure of protrusions and depressions; (B) forming a metal film 21 on the surface of the metal substrate 11, where the metal film 21 contains as the main component a metal different from the constituent metal of the metal substrate 11; and (C) annealing the metal film so that the constituent metal of the metal film is coagulated into particles.