PURPOSE: To provide a stable dense surface to an arbitrary place of the surface of a porous member by heating only the porous surface part of the member to be made dense, feeding a gas for a CVD reaction to the heated part through the pores, and depositing a solid phase.

CONSTITUTION: When a porous ceramic member 1 having open pores in at least the surface layer is not electrically conductive, the part of the member to be made dense is coated with carbon 2 to about 10μm thickness, and an alternating magnetic field is impressed with a high frequency coil 3 to heat the part to the deposition temp. of a CVD reaction. A gas for the CVD reaction is fed to the heated part through the open pores, and a solid phase 5 is deposited by the CVD reaction to make the surface of the part dense.