Provided is a sustained release sheet that includes a drug for treating nerve damage, wherein the sheet is applied to a nerve damage site, can maintain a high concentration of the drug over a long period, and promotes nerve regeneration without stimulating the nerves, even when the sheet is implanted in the periphery of the nerve damage site. Also provided is a production method for the sheet. This sustained drug release sheet for treating nerve damage is a sheet comprising a nonwoven fabric that is formed from nanofibers which include a drug such as vitamin B12 and a biocompatible polymer such as a biodegradable aliphatic polyester, and is implanted in the periphery of the nerve damage site to promote nerve regeneration.