The present invention aims at providing a composite semipermeable membrane excellent in water permeability and salt-blocking rate, a smaller content of unreacted polyfunctional amine components in the membrane, the composite semipermeable membrane avoiding the necessity of a membrane washing treatment, and the present invention also aims at providing a process for producing the composite semipermeable membrane. A composite semipermeable membrane having a skin layer, formed on a surface of a porous support, including a polyamide resin obtained by an interfacial polymerization of a polyfunctional amine component and a polyfunctional acid halide component, wherein the content of the unreacted polyfunctional amine component is 200 mg/m.sup.2 or less without removing by washing of an unreacted polyfunctional amine component after formation of the skin layer.