A material for processing includes an elastically deformable single thin plate comprising a plurality of through-holes. The plate has a first wave-like shape, which is formed in a first direction and, in which troughs and ridges are alternately connected in repetition, and a second wave-like shape which is formed in a second direction crossing the first direction and in which troughs and ridges are alternately connected in repetition. The first wave-like shape has a corrugated shape in which the ridges each include a pair of side parts rising from the corresponding troughs and an apex part connected between the pair of side parts. An apex length of the apex part along the first direction is defined as being longer than an opening length, along the first direction, between base parts of the pair of side parts.