A manufacturing method comprising: - deriving, from statistic data, a representative value of a clearance that is provided between a first workpiece (Wa) and a second workpiece (Wb), the first workpiece (Wa) and the second workpiece (Wb) structuring an airframe of an aircraft and being configured to be fastened to each other, the statistic data being obtained from measuring the clearance; characterized by further comprising: - executing a first insertion process that includes - testing insertion of a tolerance shim into the clearance when the representative value is less than a tolerance (d) of the clearance, the tolerance shim having a thickness corresponding to the tolerance (d), and - testing insertion of a double-tolerance jig into the clearance when the tolerance shim is insertable into the clearance in the testing the insertion of the tolerance shim, the double-tolerance jig having a thickness twice the tolerance (d); - executing a second insertion process that includes - testing insertion of a difference shim into the clearance when the representative value (μ) is greater than the tolerance (d), the difference shim having a thickness corresponding to a resultant of subtraction (μ - d) of the tolerance (d) from the representative value (μ), - testing insertion of a representative shim into the clearance when the difference shim is insertable into the clearance in the testing the insertion of the difference shim, the representative shim having a thickness corresponding to the representative value (μ), and - testing insertion of an addition jig into the clearance when the representative shim is insertable into the clearance in the testing the insertion of the representative shim, the addition jig having a thickness corresponding to a resultant of addition of the tolerance (d) to the representative value (μ); and - performing a process of fastening the first workpiece (Wa) and the second workpiece (Wb) in accordance with the results of the first insertion process and the second insertion process. - deriving, from statistic data, a representative value of a clearance that is provided between a first workpiece (Wa) and a second workpiece (Wb), the first workpiece (Wa) and the second workpiece (Wb) structuring an airframe of an aircraft and being configured to be fastened to each other, the statistic data being obtained from measuring the clearance; - executing a first insertion process that includes - testing insertion of a tolerance shim into the clearance when the representative value is less than a tolerance (d) of the clearance, the tolerance shim having a thickness corresponding to the tolerance (d), and - testing insertion of a double-tolerance jig into the clearance when the tolerance shim is insertable into the clearance in the testing the insertion of the tolerance shim, the double-tolerance jig having a thickness twice the tolerance (d); - executing a second insertion process that includes - testing insertion of a difference shim into the clearance when the representative value (μ) is greater than the tolerance (d), the difference shim having a thickness corresponding to a resultant of subtraction (μ - d) of the tolerance (d) from the representative value (μ), - testing insertion of a representative shim into the clearance when the difference shim is insertable into the clearance in the testing the insertion of the difference shim, the representative shim having a thickness corresponding to the representative value (μ), and - testing insertion of an addition jig into the clearance when the representative shim is insertable into the clearance in the testing the insertion of the representative shim, the addition jig having a thickness corresponding to a resultant of addition of the tolerance (d) to the representative value (μ); and - performing a process of fastening the first workpiece (Wa) and the second workpiece (Wb) in accordance with the results of the first insertion process and the second insertion process.