A joined body manufacturing method includes: a laminating step for forming a laminated body in which either a copper circuit substrate (first member) or a ceramic substrate (second member) is coated beforehand with a temporary fixing material the main ingredient of which is a saturated fatty acid, the copper circuit substrate and the ceramic substrate are stacked and positioned by the temporary fixing material which has been melted, and by cooling the temporary fixing material the stacked copper substrate and ceramic substrate are temporarily fixed; and a joining step for forming a joined body in which the copper circuit substrate and the ceramic substrate are joined by heating with pressurizing the laminated body in the stacking direction.