Resonator-integrated duct and method for manufacturing resonator- integrated duct

A method for manufacturing a resonator-integrated duct, the method comprising:

• a first step of forming a casting in which a duct portion having a first cavity and a resonator chamber having a second cavity are integrally formed with a partition wall interposed therebetween;
• a second step of removing a core that fills the second cavity through openings of a plurality of opening portions that penetrate an outer wall of the resonator chamber of the casting;
• a third step of inserting a tool through an opening of one opening portion of the plurality of opening portions, and forming a communication hole in the partition wall at a position facing the opening of the one opening portion, the communication hole connecting the resonator chamber and the duct portion;
• and
• a fourth step of closing the openings of the plurality of opening portions with lid members.