It is intended to provide an agent for promoting corneal neuritogenesis containing PACAP, a PACAP derivative or a pharmaceutically acceptable salt thereof, in particular, an agent for promoting corneal neuritogenesis aiming at improving corneal sensitivity, treating dry eye and treating corneal epithelial injury due to an effect of promoting corneal neuritogenesis. This agent for promoting corneal neuritogenesis is useful as a drug for ameliorating reduction in corneal sensitivity following corneal surgeries such as laser keratonomy (LASIK) and corneal grafting or cataract surgery, reduction in corneal sensitivity accompanying corneal neurodegeneration and dry eye symptom and corneal epithelial injury accompanying such reduction in corneal sensitivity. Moreover, it is useful as a drug for ameliorating dry eye symptom, reduction in corneal sensitivity and corneal epithelial injury in patients with dry eye, and a drug for ameliorating corneal epithelial injury and dry eye symptom and reduction in corneal sensitivity accompanying therewith.