The spectral sensor for surface-enhanced Raman scattering (SERS) of the present invention is prepared with a single-crystal noble metal nanowire which has a high quality, a high purity and an excellent shape. Thus, the sensor can be used for in-situ detection. Further, since a sensor site for reacting with irradiated laser beam can have a controlled structure, shape and a controllable hot spot, reliability and reproducibility are excellent and sensitivity of the sensor can be improved. In addition, with the optimization of a mechanical structure of a single noble metal single-crystal nanowire and a polarization direction of laser beam, sensitivity, selectivity and signal intensity become high. Furthermore, the spectral sensor for surface-enhanced Raman scattering of the present invention can be advantageously used not only as a sensor for detecting chemicals but also as a biosensor and a sensor for diagnosis of disease.