PROBLEM TO BE SOLVED: To provide optical waveguide parts which do not give rise to a problem in adhesion over a long period of time in the optical waveguide parts fixed by adhesives by inserting an optical waveguide insertion type optical element into a groove formed in the optical waveguide. SOLUTION: A polyimide optical waveguide is used for the optical waveguide of the optical waveguide parts formed by inserting the optical waveguide insertion type optical element 3 into the groove formed in the optical waveguide and fixing the element by the adhesives 4 and the optical waveguide insertion type optical element of which at least the one surface is formed of a polyimide film is used for the optical waveguide insertion type optical element 3. As a result, at least one of the two adhesive surfaces of the optical waveguide and the optical waveguide insertion type optical element is the polyimide to the polyimide and, therefore, excellent adhesion reliability is obtd. and the characteristics stable even after in a long-time heat cycle test is obtd. Namely, the optical waveguide parts have an effect of the excellent long-term reliability.