Tungsten (W) nanopyramids coated with noble metal films can function as highly coherent electron sources. This study aims to grow nanopyramids by employing long-distance surface diffusion of palladium (Pd) atoms. Collodion (also known as nitrocellulose) containing PdO powder was coated on the regions far from the W tip and was used as a source of Pd atoms. Annealing the W tip in UHV resulted in a change in the field ion microscopy (FIM) pattern. The resultant FIM images showed three equivalent {211} planes adjacent to the {111} planes of the W tips. However, with the proposed method, the apex of the W tip was not a single atom, but a wide triangle corresponding to the subsurface of an ideal nanopyramid.