PURPOSE: To enable exact display by generating a stepwise output value in accordance with an input so that the plural segments in a display part are operated stepwise by said input.

CONSTITUTION: A resistance part 44 is printed and baked on a circuit board 43 formed of ceramics or enamel and lead legs 45 which are fine conductors are connected to the respective points in the part 44. Sliding contact plates 46 are provided at the ends of the legs 45, and a sliding contact part 47 is formed along the moving locus of the contact point 35 of a detecting stylus 34. The characteristic in the change of the resistance value changes stepwise while the contact point moves along the part 47, and the respective resistance values are set by trimming the part 44 in such a way as to have the gap in the tolerance region of the boundary input value for each segment in the display part.