PURPOSE: To offer a metal lath working device possible to work a metal lath having sharp edges excellent dimension accuracy and uniform lath mesh shape as regards a metal lath working device, especially, a metal lath working device to work a metal lath through a battery or a heat exchanger.

CONSTITUTION: A punch 1 having a blade of a lath mesh shape moving vertically and horizontally and a flat die 2 making a vertical pair with the punch 1 are provided and a primary-worked metal lath 6 worked as a thin sheet 5 is passed between the punch 1 and the flat die 2 is passed through a tension roller 3. A roller 4 having grooves of lath mesh shape 4a corresponding to the lath mesh shape of the primary-worked metal lath 6 on the outer periphery is provided.