PURPOSE: To improve productivity and to decrease fluctuation in resistance value and sliding noise by dividing an insulating board after print-baking of rear electrodes, resistor face electrodes, and resistive elements, by printing end-face electrodes, and by baking a workpiece at a temperature lower than the baking temperature of a resistive element.

CONSTITUTION: Semi-fixed rheostat elements are formed on an insulating board 1 as a monolithic body of three or more arrays. Resistor face electrodes 2 are printed on this insulating board 1 and baked. This step is followed by print- baking of rear electrodes 3 and then of resistors 21. And, the insulating board 1 is divided and end-face electrodes 4 are printed, which is then baked at the baking temperature of the resistor 21. Further, plating resist 5 is printed and hardened except at end faces and rear electrodes, and plate electrodes 6 are formed by electric plating. After the steps of forming the plating electrodes 6, removing the plating resist 5, and the inspection, components such as brushes are assembled, thereby completing the workpiece.