PURPOSE: To produce an expanded metal with high efficiency by feeding diagonally a sheet material between a stationary lower die and movable upper die and moving back and forth the movable upper die only in the vertical direction.

CONSTITUTION: The sheet material 5 is intermittently fed between the stationary lower die 1 having a rectilinear blade 2 and the movable upper die 4 having a waveform blade 7 by rollers 6, 7 in the diametral direction at a specified angle θ with the blade 2. The die 4 is vertically moved to lance the sheet 5 as well as to form mesh 9 by lancing and expanding. The expanded metal is thus formed. The relation shown by the equation is satisfied in this stage where the pitch of the blade 3 of the die 4 is designated as P, the infeed angle of the material 5 to the blade 2 of the die 1 as θ and the length to feed intermittently the material 5 at every one stroke of the die 4 as (l).