Provided is: a cell culture membrane, which is free from materials derived from living organisms, can easily be industrially mass-produced, exhibits superior long-term storage properties and chemical resistance, has excellent cell adhesion properties and long-term culture properties and is capable of replicating a cell adhesion morphology that is similar to that of collagen derived from living organisms and being used for conventional cell cultivation. Also provided are a cell culture substrate, and a method for manufacturing the cell culture substrate. In the present invention, as a cell adhesion layer, a polymer membrane represented by formula (I) is formed on the base of a cell culture substrate so as to have a membrane thickness equal to or greater than 0.2 μm (in the formula, R1 and R2 represent a —(CH2)n—NH2 moiety (n is an integer of 1-10 inclusive.) or H, with at least one of R1 and R2 being a —(CH2)n—NH2 moiety. Moreover, l and m are positive integers expressing polymerization degree).