The autonomic nervous system was differentiated on the basis of the observations and claims of Gaskell and Langley more than a century ago. In 2016, a study was published arguing that the classification of the autonomic nervous system should also be redefined in light of the recent development of molecular biology tools that were unavailable at the time. The paper argued that the sacral division, which had been classified as the parasympathetic nervous system, should be classified as the sympathetic nervous system, like other spinal cord divisions, which sparked considerable debate. In this review, the classification of the sacral division, as well as the idea of the autonomic nervous system, are investigated, along with the arguments that support them. Various perspectives, including anatomical, physiological, and pharmacological criteria for identifying the sympathetic and parasympathetic nervous systems, were applied to a review of the sacral division. The function and anatomy of the autonomic nervous system in the pelvic region, where the target organs of the sacral division are located, were also reviewed. As a result, it was determined that classifying the sacral division as sympathetic is more or less inappropriate and would rather cause confusion in the clinical field. In spite of this, it appears important to reevaluate the current understanding of anatomy, including the autonomic nervous system, in light of the advancement of molecular biology technology and the accumulation of knowledge.