FEM simulation of SPPs in nanostructures based on metal-insulator-metal (MIM) heterostructure. The numerical calculations weill be applied to design of a novel optical probe for scanning near-field optical microscope (SNOM). The FEM simulation has been done with both two-dimensionally- and three-dimensionally-designed models. The MIM structure may act as band-pass filter for SPP excitation, and twin hole in thick metallic layer of the structure could waveguide the SPP from internal insulator layer to the surface of metallic layer. SPPs come out from the holes may join and create single bright point light source for SNOMs. Experimental study of the prototypical probe is also conducted by using optical fiber optics, vacuum evaporation system, scanning electron microscope, and focused ion beam milling.