In a soundproof structure body including a tubular tube body having an opening portion, and a resonance type soundproof structure, in which a phase difference θ, at an upstream of the resonance type soundproof structure, between a reflected wave in the resonance type soundproof structure and a reflected wave of a transmitted wave transmitted through the resonance type soundproof structure and reflected by the opening portion satisfies Inequation |θ - π| ≤ π/3 with respect to a resonance frequency of the resonance type soundproof structure. This soundproof structure body can effectively offset a reflected wave from a resonance type soundproof structure body by opening end reflection by appropriately specifying positions of the resonance type soundproof structure and the opening end portion of a duct, a tube line, or the like to improve an absorbance of a single resonance type soundproof structure.
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