SOUND-BLOCKING SHEET MEMBER, SOUND-BLOCKING STRUCTURE USING SAME, AND METHOD FOR MANUFACTURING SOUND-BLOCKING SHEET MEMBER

An object of the present invention is to provide a resonator that is relatively lightweight, has high sound-blocking performance overwhelming the law of mass action, and is excellent in terms of manufacturability and durability. The resonator includes at least a sheet and at least one resonance portion. The resonance portion is provided in contact with a sheet surface of the sheet, and the resonance portion includes a weight portion and a base portion. The weight portion is supported by the base portion and has a larger mass than the base portion, and the weight portion has a penetration portion. The base portion is in contact with a surface on a resonance portion front end side of the weight portion and covers the weight portion.