PURPOSE: To enable manufacture of an expanded metal having uniform mesh structure by stretching a metallic plate having zigzag slits by pressure in the direction of thickness and then stretching it in horizontal direction by pressure.

CONSTITUTION: Many slits are pierced in zigzag arrangement on a metallic plate such as a copper plate at specified line spacing d1 and mutual spacing d2. The perforated metallic plate 4 is stretched by pressure in the direction of thickness by a press that uses dies 5 which mesh in saw-toothed form keeping spacing d2. It is formed into the shape of a saw in which the spacing d2 becomes the top of a crest or the bottom of a trough. The slits 1 is expanded in the direction of blanking. Then, the perforated metallic plate 4 corrugated by previous process is pressed flat by a pressing device that uses dies 6 or rollers 7. The plate is stretched in the direction along the shorter side of the slit and the boundary between the spacing d2 and line spacing d1 is twisted. Thus, an expanded metal is formed.