A helical fine structure of the present invention is characterized by including: a phytoplankton having a helical shape and selected from a group of cyanobacteria called Spirulina and a surface modification layer formed on the phytoplankton. The surface modification layer includes at least one metal plating layer. Thereby, the helical fine structure can be utilized as an electric-wave shield or an absorber. Moreover, a method for producing the helical fine structure is characterized in that a prestep of a step of forming the surface modification layer on the phytoplankton having a helical shape includes a washing step with an organic solvent to remove an outer membrane from a surface of the phytoplankton.
