To provide a method for manufacturing a thermosetting aromatic polyimide joined belt capable of easily corresponding to the production of a belt having an arbitrary size without using an adhesive.

The method for manufacturing the endless polyimide joined belt having a joint in its lateral direction has a film manufacturing process for manufacturing a thermosetting aromatic polyimide precursor film, a bonding process for superposing the end parts of the polyimide precursor films to heat- seal them to form a tubular body having a joint part formed thereto and an imidation process for heating the tubular body in a fixed state or under tension to imidate the polyimide precursor.