The present invention maintains the performance at high temperature and high pressure, and aims to provide a highly composite semipermeable membrane water permeability. Composite semipermeable membrane of the present invention includes a substrate, a porous support layer positioned on the substrate, and a separation functional layer located on a porous support layer, the separation function layer is crosslinked wholly aromatic polyamide has a fold structure comprising projections and recesses as a main component, when the surface observation in pure water by an atomic force microscope separating functional layer, deformation amount when pushed projections with a force of 5nN is 2.5nm account for the convex portion is 40% or more comprising less, and is the intermediate value of the convex height is 100nm or more, and the thickness of the separation function layer in the convex portion is 20nm or less.