NOVELTY - Ceramic product comprises: an oxygen separation membrane (15) made of an oxide ceramic with a perovskite structure which is an oxygen ion conductor; at least one ceramic connecting member bonded to the oxygen separation membrane; and a bond part between the membrane and member, where: the bond part is formed from a crystalline-amorphous composite material; and the bond part is formed of the oxide components comprising (in mass%) silicon dioxide (40-75), aluminum trioxide (5-20), sodium oxide (5-20), potassium oxide (5-20), magnesium oxide (0-3), calcium oxide (0-3) and strontium oxide (0-3).    USE - The ceramic product is useful in solid oxide fuel cells.    ADVANTAGE - The ceramic product: has greater air tightness (seal function) and mechanical strength; is suited to repeated use at high temperatures; and provides excellent heat resistance and durability to solid oxide fuel cells, capable of maintaining air tightness for long-term, without any cracks.    DETAILED DESCRIPTION - Ceramic product comprises: an oxygen separation membrane (15) made of an oxide ceramic with a perovskite structure which is an oxygen ion conductor; at least one ceramic connecting member bonded to the oxygen separation membrane; and a bond part between the oxygen separation membrane and the connecting member, where: the bond part is formed from a crystalline-amorphous composite material characterized by having leucite crystals precipitated in a dispersed state in a glass matrix; the bond part is formed of the oxide components comprising (in mass%) silicon dioxide (40-75), aluminum trioxide (5-20), sodium oxide (5-20), potassium oxide (5-20), magnesium oxide (0-3), calcium oxide (0-3) and strontium oxide (0-3); and a thermal expansion coefficient of the bond part is 10-14x 10-6 K-1. An INDEPENDENT CLAIM is also included for a bond material for use in an oxygen separation membrane and a ceramic connecting member, comprising a powder of the crystalline-amorphous composite material characterized by having leucite crystals precipitated in a dispersed state in a glass matrix, a solvent for dispersing the powder, and an organic compound that functions as a binder.    DESCRIPTION OF DRAWING(S) - The figure shows the configuration of an oxygen separation membrane element.    Cap member (12)    Cylindrical porous substrate (14)    Oxygen separation membrane (15)    Ring member (16)    Insertion hole (17)