The present invention provides a method for manufacturing a polymer optical waveguide, which achieves wider material selectivity, improved processing reproducibility and yield, and low cost. This method for manufacturing a polymer optical waveguide comprises: disposing a core forming curable composition on the surface of a mold having recessed portions each corresponding to a core shape; affixing a transfer film to the surface of the mold while pressing the transfer film thereto in a predetermined direction, and removing the excess core forming curable composition while filling the recessed portions with the core forming curable composition; curing the core forming curable composition to form cores; peeling the transfer film from the mold to transfer the cores onto the transfer film; and forming a first clad so as to cover the cores on the transfer film.