The present invention aims at providing a process for producing a dried composite semipermeable membrane having extremely small amount of content of unreacted components, outstanding water permeability and salt-blocking rate even after drying treatment, and outstanding contamination resistance and durability. The present invention relates to a process for producing a dried composite semipermeable membrane comprising the steps of: preparing a composite semipermeable membrane having a skin layer including a polyamide resin obtained by reaction between a polyfunctional amine component and a polyfunctional acid halide component formed on the surface of a porous support; preparing a washed composite semipermeable membrane by washing the composite semipermeable membrane; preparing a treated composite semipermeable membrane by contact of a moisturing solution including a moisturizer and a hydrophilization agent only to the surface of the porous support of the washed composite semipermeable membrane and by contact of a protecting solution only to the surface of the skin layer of the washed composite semipermeable membrane; and drying the treated composite semipermeable membrane.