1. A method of detecting nerves, comprising: step 1 of irradiating a sample with excitation light; step 2 of detecting Raman scattering light from the sample; step 3 of calculating an intensity ratio of a wave number within a specific range of the Raman scattering light detected in the step 2 or extracting a feature of the intensity ratio and subjecting the feature to multivariate analysis and/or statistical analysis; and step 4 of specifically displaying nerves containing unmyelinated nerves, using as an index the intensity ratio or a result from the multivariate analysis and/or the statistical analysis.