A frame member includes a frame body and a sheet member. The frame body has a front surface, a back surface, an opening penetrating in a front and back direction of the frame body, and a protruding portion. One of the front surface and the back surface has an attachment groove. The sheet member constituted by a mesh-like member is stretched over the opening. The protruding portion is configured such that, after the sheet member is arranged in an area where the protruding portion is to be formed, a material for the frame body in an unsolidified state is filled and is solidified, to thereby form the protruding portion together with the frame body and fix the sheet member in a stretched state over the opening. The sheet member has reached one of the front surface and the back surface along an inner circumferential surface of the frame body.