Resonator with high heat resistance

A resonator comprising:

• an upper case defining a portion of a resonance chamber and having a communicating hole communicating with said resonance chamber;
• a lower case integrally joined to said upper case and defining said resonance chamber together with said upper case;
• an air pipe which is blowmolded with said upper case being inserted, which is joined to an outer surface of said upper case where said communicating hole opens, an inside of which forms a gas passage, and which is defined with a through hole forming a common hole with said communicating hole, and
• a ring-shaped coupling body which is disposed at a peripheral edge portion of said communicating hole in advance, joins said upper case and said air pipe to each other, and is defined at a center portion of said ring-shaped coupling body with a through hole,
• wherein said air pipe is blow molded by using a polypropylene resin,
• said lower case and said upper case are molded by using a nylon resin, and
• said ring-shaped coupling body is molded by using an intermediate resin which can be joined to said polypropylene resin and said nylon resin.