To prevent a joining material from excessively entering into the inside of an SiC porous body in joining and to carry out proper joining.

The joining method for joining the porous body comprising SiC with the joining material includes at least a step for infiltrating a nitride of aluminum or boron into the porous body, a step for applying carbon on a joining surface of the porous body and a step for joining the porous body with the joining material on the joining surface. As a result, the excess entering of the joining material to the inside of the SiC porous body is prevented to inhibit the reaction of the porus body with the joining material and the porous body and the joining material are properly joined.