To provide a method for manufacturing a resin film bag which can be efficiently affixed with an identification code having traceability, without hindering the production speed of other processes.

In the manufacture of a resin film bag imparted with the traceability, a printing process of the indicator code 5 by a computer-controlled printer, a sealing process for performing bottom sealing procedures to seal the bottom of the bag, and a cutting process for separably cutting each resin film bag 1, are executed, in an in-line mode, to a cylindrical thermoplastic resin film 2.