Bondability and interfacial reaction between dielectric and insulator layers have been examined to obtain a basic understanding of bonding mechanisms; Lead-containing complex perovskite was used as a dielectric material. Two kinds of glass-ceramics were used as insulator material; lead borosilicate glass containing Al2O3 (insulator A) and the same containing Al2O3 and MgO (insulator B). Dielectric and insulator layers did not bond when insulator A was used. When insulator B was used, however, strong bonding was achieved between the two layers by firing the powder compacts at temperatures between 800 degrees and 1000 degrees C. Addition of MgO to lead borosilicate glass increased the thermal expansion coefficient to that of the dielectric and enhanced the formation of reaction layers, resulting in good bonding. Two reaction layers were identified. The main reaction products were enstatite and bredigite for one-layer contacting the dielectric, and enstatite and a compound with the same diffraction pattern as that of faujasite for the other layers contacting insulator B.