There is provided a method of producing a fluid channel device including laminating a plurality of polyimide films including at least one polyimide film having a port and at least one polyimide film having a channel, the polyimide films including at least one thermoplastic polyimide film; and adhering a plurality of the polyimide films by applying heat such that the ports are communicated with the channels. There is also provided the flow channel device produced by the method.