Composite semipermeable membrane and method for producing same

A composite semipermeable membrane comprising a porous support layer and a separation functional layer provided on the porous support layer, wherein

• the composite semipermeable membrane has a first surface which is a surface on a separation functional layer side and a second surface which is a surface opposite to the first surface,
• the separation functional layer contains a crosslinked polyamide, and
• an amino group density measured by a scanning transmission electron microscope (STEM) in a cross section in a thickness direction of the separation functional layer satisfies Nb/Nd≤0.40,
• Nb:
• an amino group density of a region b,
• Nd:
• an amino group density of a region d, and
• regions a to e:
• regions obtained by dividing the cross section into five equal parts in the thickness direction of the separation functional layer, the regions a to e being aligned from the first surface toward the second surface.