The open air layer-type vibration reduction structure is provided with at least one plate-like member of which the obverse surface faces toward the open space side; and a frame spaced at an interval from the reverse surface of the plate-like member, and an air layer is formed between the plate-like member and the frame. An air-permeable ventilation portion is formed at least one of the plate-like member and the frame, such that the average value of the flow resistance on the surface of at least one of the plate-like member and the frame, which forms an air layer, is in a range greater than 0 N·s/m3 and equal to or less than 1,000 N·s/m3. The ventilation portion may be configured such that the sound pressure level generated within the air layer by applying an external force to the air layer is reduced by 3 dB or more.