A glass ceramic composition which consists essentially of an inorganic material powder having a melting point or a glass transition point of at least 1,000° C. and a glass powder having a glass transition point of from 450 to 800° C., wherein the average of the major axes L of particles of the above inorganic material powder is from 0.5 to 15 μm, and the average of the ratios L/W of the major axes L to the minor axes W is at most 1.4. Further, a glass ceramic composition which consists essentially of, as represented by mass percentage, from 10 to 58% of an inorganic material powder having a melting point or a glass transition point of at least 1,000° C. and from 42 to 90% of a glass powder having a glass transition point of from 450 to 800° C., wherein the glass powder consists essentially of, as represented by mol %, SiO2: 35 to 70%, B2O3: 0 to 30%, Al2O3: 3 to 18%, MgO: 0 to 40%, CaO: 0 to 19%, BaO: 0 to 35% and ZnO: 0 to 9%.