Intake device for an internal combustion engine

A modular plastic engine manifold has a module comprising the air intake distribution duct (2), separate modules for the branch ducts (6), and modular flanges (9) for joining to the engine. The branch ducts (6) are injection or blow molded and are attached to the flanges during injection molding of the flanges (9). The distribution duct is blow molded and attached by welding or by molding.