A ceramic multilayer substrate exhibiting reduced pealing and breakage of an internal conductor disposed between a ceramic layer serving as a base member and a ceramic layer for restricting shrinkage includes a first ceramic layer 11, a second ceramic layer 12 laminated so as to come into contact with a principal surface of the first ceramic layer 11, and an internal conductor 13 disposed between the first ceramic layer 11 and the second ceramic layer 12, a phosphorus component layer 16a is disposed in the first ceramic layer 11 with a concentration gradient in which the concentration decreases in a direction away from the internal conductor 13.