Abstract: Electromagnetic waves are uniformly distributed on the light-receiving surface side by taking advantage of their property of being easily concentrated in sharp parts, and the front area (SA) on the emission surface side is made larger than the back area (SB) on the light-receiving surface side (SA/SB>1), thereby forming a more moderate electric field region. A reduced gold fine particle group (average particle size: 20 nm) was self-assembled on a transparent polyester resin film and half-submerged and fixed. This base material was repeatedly immersed in an electroless gold plating solution so that gold particles were deposited on the gold fine particles. 10 microliters of a protein solution was added dropwise to this nanostructured substrate, and crystallized by a hanging drop vapor diffusion method.