Metal-ceramic composite bodies

A metal-ceramic composite body has a metallic member (4) and a ceramic member (1) provided with a recess (5) and a projection (2) respectively and integrally joined by inserting the projection into the recess. The recess of the metallic member is provided with a stepped portion to increase its inner diameter at an opening portion (3) thereof, and a brazing metal (6) is interposed at least in a gap between the stepped portion and the projection of the ceramic member. Alternatively, a groove is provided substantially all over the entire periphery of the projection of the ceramic member in the vicinity of an end of a joined portion between the metallic member and the ceramic member, and a brazing metal is interposed at least between an edge of the groove and the recess of the metallic member. Besides the above, the axial length L2 of the joined portion and the diameter D of the projection may be set to satisfy the following relationship: t