Raman scattering signals can be enhanced by several orders of magnitude on surface‐enhanced Raman scattering (SERS) substrates made from noble metal nanostructures. Some SERS substrates are even able to detect single‐molecule Raman signals. A novel silver nanobud (AgNB) substrate with superior SERS activity was fabricated with a solid‐state ionics method. The AgNB substrate was formed by tightly collocated unidirectional 100 nm size silver buds, presenting a highly rough surface topography. Distinct SERS signals of single λ‐DNA molecules in water were detected on AgNB substrates. AgNB substrates were compared with disordered silver nanowire (AgNW) substrates manufactured by the same method through the SERS detection of λ‐DNA solutions. This original AgNB substrate provides a reliable approach towards trace analysis of biomacromolecules and promotes the utilization of the SERS technique in biomedical research.