Abstract: The present invention relates to a metallic device for near-field optical microscopy and spectroscopy, as well as to a method of preparing it. Said device comprises a single body (1) with longitudinal prolongation (2), nanometric apex (4) and has at least one trimming (3) on its surface, being applied as a probe of high optical efficiency, with adequate dimensions and details that enable the best photon-plasmon coupling, enabling the analysis, with high space resolution, of structures of nanometric dimensions with high efficiency and reproducibility.