Patent ID: 8863894

Claim:
A silencer comprising: a frame member which is provided to be perpendicular to a direction of a fluid passage in a duct in which a fluid flows and is assembled in a four-sided frame shape; and a silencing porous plate in which an outer edge is fixed to the frame member and is configured of an approximately rectangular plate member having a plurality of holes formed thereon, wherein the plurality of holes are disposed in one row with intervals to each other along one direction, the plurality of holes forming the one row are disposed in a plurality of rows in a direction perpendicular to the one direction, positions of the holes in adjacent rows are shifted in the one direction and disposed in a zigzag pattern, and a disposition interval of the holes of an outer edge hole row forming one row in at least two sides opposite to each other in the silencing porous plate is set to be larger than a disposition interval of the holes of a row inside the outer edge hole row.