A noise reducer for construction machinery, which efficiently reduces noise at low cost with durability, is provided. For this purpose, lamination plates (8) which are the plates being laminated are bonded, discretely at a predetermined interval (a1), to a part of or the entire of a noise generating element. Lamination plates (8A, 8E) may be bonded discretely at a plurality of kinds of bonding intervals (a1, a2). The lamination plates (8) with the different number of laminations may be bonded according to a noise generating element.