A method of manufacturing a joined body, including: covering a first area and a second area of a first substrate with a sheet of resin in uncured state; separating a part of the sheet covering the second area from the first substrate, the separating performed after the covering; and joining the first substrate with a second substrate by arranging the second substrate to face the first substrate with a part of the sheet covering the first area between the first substrate and the second substrate, and curing the resin in the part of the sheet covering the first area, the joining performed after the separating. In the method, during the separating, a phase difference δ between stress and strain in the part of the sheet covering the second area is no greater than 48 degrees.