PURPOSE: To restore a metal conductor for connection on a sintered conductor by performing heat treatment at a specific temperature when preparing the surface of the sintered conductor after chemically dissolving and eliminating a metal conductor on the sintered conductor.

CONSTITUTION: Nickel-plated film 3 and gold-plated film 4 are formed on tungsten sintered body 2 using a ceramic substrate 1 with the tungsten sintered conductor 2, thus forming a metal conductor for connection. After that, when performing heat treatment, a plated film blister 5 is generated from the interface between the sintered conductor 2 and the nickel-plated film 3. For restor the metal conductor for connection, first a ceramic wiring board is dipped into aqua regina, thus dissolving and eliminating the nickel-plated film 3 and the gold-plated film 4. Then, it is dipped into tungsten dissolution liquid as the treatment for preparing the surface of the sintered body and further liquid blast treatment is performed and then heat treatment is performed for the wiring board at 500-1650°C, preferably 1000-1600°C thus obtaining a surface where the conductor for connection can be reproduced.