PURPOSE: To obtain a lath for building connecting the mesh without cutting by slitting the metallic plate feeding at a fixed speed by the upper edge connecting the trapezoidal edge regulating the angle of mutual size and by widening and deforming from a flat hexagon to a regular hexagon.

CONSTITUTION: A slit is formed by dropping the upper edge having the angle (a) of less than 30° making the slant side and bottom side, on a metallic plate 1 and is widened with pushing along the edge shape. The metal lath 20 connecting the mesh 21 thus obtd. is fed out to the arrow mark direction passing through the space between the 1st pinch roll 12 and the 2nd pinch roll 14. At this moment due to the rotation speed of the roll 14 being made faster than that of the roll 12, a tension is acted on the metal lath 20 with the differential speed caused between both. The metal lath 20 is thus stretched out slowly as shown in the figure and when it is rolled out from the roll 14, a lath for building connecting a regular hexagonal mesh 21 which is solid and has no fear of causing a crack on a mortar nor break away connecting the mesh 21 of almost regular hexagon by deforming the mesh 21 to nearly regular hexagon, is obtd.