| abstract |
A composite semipermeable membrane comprising a substrate, a porous support layer formed on the substrate, and a separation functional layer formed on the porous support layer, wherein the separation functional layer is a cross-linked total aroma And a ratio of (mole equivalent of carboxy group) / (mole equivalent of amide group) among the functional groups contained in the separation functional layer, which is mainly composed of a group polyamide, and contains a carboxy group, and is 0.40 or more, and A composite semipermeable membrane having an average ratio of oxygen atoms / nitrogen atoms on the front and back of the separation functional layer of 0.95 or less. |