The present invention provides a method for producing a virus vector, which involves a step of culturing a cell capable of producing the virus vector in a culture medium containing a retinoic acid compound, a histone deacetylase-inhibiting substance and a substance capable of forming a chelate； and a culture medium for use in the production of a virus vector, which is characterized by containing a retinoic acid compound, a histone deacetylase-inhibiting substance and a substance capable of forming a chelate as active ingredients.
