A separation membrane according to the present invention is characterized by having a porous tube containing an alumina as a main component and an attachment member disposed in a connection position of the porous tube, wherein the porous tube and the attachment member are bonded by a ceramic oxide-based bonding agent containing 17 to 48 wt % of SiO2, 2 to 8 wt % of Al2O3, 24 to 60 wt % of BaO, and 0.5 to 5 wt % of ZnO as essential components and containing at least one of La2O3, CaO, and SrO, and a thin zeolite layer is formed on a surface of the porous tube. The attachment member is bonded to the porous tube before the formation of the zeolite layer. Therefore, the bonding agent can have a melting temperature higher than 600° C., which is the upper heatproof temperature limit of the zeolite. Thus, the ceramic oxide material for the bonding agent can be selected from a wider range of compositions such as glass compositions (without limitations on the glass softening temperature).