PURPOSE: To manufacture a metal fine wire having a deformed cross section with high accuracy by forming both sides of a work roll in spherical face, supporting it with its abutment by the end face of a metal chip and forming the composition to abut a backup roll to the roll outer peripheral face.

CONSTITUTION: Two pieces of work rolls 1, 2 support their both end faces formed nearly in spherical face by the end faces of chips 11, 11 and 12, 13 respectively with their abutments. The backup rolls 5, 6 consisting of the bearings pivotally supported respectively on housings 3, 4 are abutted on the outer peripheral face of the rolls 1, 2. In case of machining a metal wire, the chip 13 is adjusted by moving in the axial direction via a worm 20 and worm gears 19, 17 by a handle 18 to set to the core of the roll groove of the rolls 1, 2. The roll 5 pressurizing force of the housing 3 is adjusted via a worm 10, worm gear 10a and spacer 7 by a handle 9 at the same time. The metal fine wire with deformed cross section can thus the manufactured with high accuracy.