Providing a stable supply means, means and corneal endothelial preparation that can be efficiently grown in the corneal endothelium. The adhesion promoter of endothelial cells comprising a Rho kinase inhibitor, a Rho culture of endothelial cells including kinase inhibitors, cornea comprising a Rho kinase inhibitor preservative solution, the cornea, comprising the step of culturing corneal endothelial cells using the culture the method of endothelial formulation.