A polymeric optical waveguide module has: a light-emitting element; a polymeric optical waveguide film having a lower clad, a core, an upper clad, an optical path changing mirror surface provided at one end of the polymeric optical waveguide film and a guided light leakage portion on at least one of a lower surface of the core and an upper surface of the lower clad; and a monitoring light-receiving element that monitors light emitted from the light-emitting element. The light-emitting element, the polymeric optical waveguide film and the monitoring light-receiving element are aligned with each other so that the light emitted from the light-emitting element is reflected by the optical path changing mirror surface to be guided through the core and part of the light emitted from the light-emitting element is received by the monitoring light-receiving element via the guided light leakage portion.