A method for manufacturing a foam rubber by foaming a polymer latex is provided, wherein the polymer latex used has a solids content of 60.0 wt % or more, comprises 0.001 to 1.0 part by weight of antifoaming agent relative to 100 parts by weight of polymer in the polymer latex, and has a viscosity at 25° C. of 370 cps or less when the solids content is controlled to 66.0 wt %.