PURPOSE: To obtain a three-dimensional reticulated material easy to work and uniform in strength by drawing out a solid body made up of plates on which many specified rifts are made to the direction of opening of the rifts.

CONSTITUTION: A plate 2 of metal, etc. is creased and folded to a corrugated form. Rifts 10 are made alternately on either upper or lower creases at right angles to the upper creases 6 and lower creases thus formed to form a number of sectional creases 6a, 8a. Then, cross rods 12 of steel, etc. are provided to each sectional crease at right angles to above-mentioned creases, and contact points are fixed by welding, etc. A three-dimensional reticulated structure can be obtained by drawing out in the direction of opening of the rifts 10. If desired, a stronger reticulated material can be obtained by arranging longitudinal rods 13 in the direction of elongation at a specified pitch.