Compensation wires for Pt/Pd thermocouple was manufactured using Cu/Ni alloys. Their thermoelectric voltage has been tested from room temperature to about $150^{circ}C$. Alloys of $Cu_{95.5}Ni_{4.5}$ and $Cu_{89.5}Ni_{10.5}$ introduced only small emf differences to Pt/Pd thermocouples, indicating a real possibility of industrial use. Above $1000^{circ}C$, the temperature difference was expected to he small as ${pm}0.5^{circ}C$, and the difference would be minimized by adjusting the Ni content with a small amount.