A joint structure for jointing a connecting member to an opening end of a glass-like carbon hollow deformed pipe, which comprises the connecting member, the member being a member wherein a flange portion is formed to be integrated with an outer periphery of a sleeve portion which can be inserted into the glass-like carbon hollow deformed pipe, a sealing material arranged on an outer periphery of the opening end of the glass-like carbon deformed pipe, and a holding member for sandwiching this sealing material between the holding member itself and the flange portion of the connecting member to hold the sealing material, wherein the holding member is fastened and fitted onto the flange portion through a fastening means so as to compress the sealing material held between the holding member and the flange portion, thereby jointing the connecting member to the opening end of the glass-like carbon deformed pipe.