PURPOSE: To recover conductivity easily without depending upon conductor plating, soldering, etc., by filling a through-hole of defective conduction with Ga based metallic cement such as Ga-Cu, Ga-Ni and Ga-Au and curing the metallic cement.

CONSTITUTION: A defective conductive through-hole 6, which is generated in an inter-layer through-hole having a diameter of 0.80mm in a two-layer printed board 5, in which patterns 2 composed of 50μm copper are executed between two glass epoxy substrates 1 in thickness of 1.6mm and onto a top face and an underside and conductor plating 4 consisting of 50μm copper is executed into a hole 3, and from which a conductor is missed, is filled with the metallic cement 7 of 80wt.% Ga-Cu under the state at 30°C, and the metallic cement 7 is cured for five hr. Accordingly, since conductivity can be recovered simply only by filling the defective conductive through-hole with the Ga group metallic cement and curing the metallic cement without depending upon conductor plating, soldering, etc.