PURPOSE: To obtain a heat conductive substrate on which a micro-scopic and complicated heat-conductive circuit pattern can be formed using electric insulating material.

CONSTITUTION: This heat conductive substrate is provided with a good heat conductive metal plate 1, which is patterned in the desired form, and an aluminum nitride film 3 formed at least on one of the main surfaces of the good heat conductive metal plate. The aluminum nitride film 3 is formed by providing an aluminum layer 2 on the main surface of the good heat conductive metal plate, and nitride ions are implanted into the aluminum layer 2.