To facilitate measuring of glass necessary for bonding and make the bonding work more efficient by raising a solid electrolytic tube on the inside surface of an insulating ring, arranging a binder mainly composed of glass in the clearance between the both, and melting the binder to connect both.

A solid electrolytic tube 1 is raised on the inside surface of an insulating ring 2 with the upper opening end downward, a binder 4 mainly composed of glass is arranged in a clearance 3 formed between the circumferential surface of the solid electrolytic tube 1 and the inside surface of the insulating ring 2, and this is melted to bond the solid electrolytic tube 1 to the insulating ring 2. A quantity necessary for bonding of the binder 4 is calculated converted with respect to the length of long fiber having a diameter smaller than the width of the clearance 3 and is cut into which are to be short fibers. Thus, even when the glass short fibers are arranged in the clearance 3, no space is generated between the glass short fibers, and the bonding can be performed without leaking the melted glass from the clearance 3.