To solve a problem about warpage of a steel sheet due to a difference in temperature raising rate between an overlapped part and a one-sheet part. This manufacturing method includes: a step of heating an overlapped blank; a step of transferring the heated overlapped blank; and a step of performing presswork on the heated overlapped blank by using a die, in which in the heating step, when sheet thicknesses of the first and second steel sheets are set to t1 and t2, respectively, and an average heating rate at a sheet temperature from 20 to 800°C of a portion with a total sheet thickness (tl + t2) of an overlapped portion, and that of a non-overlapped portion are set to V and vl, respectively, the total sheet thickness (tl + t2) is 2.5 to 5.0 mm, a maximum length L of the overlapped portion is 100 to 1100 mm, an area S1 of the first steel sheet, an area S2 of a portion, of the second steel sheet, which is overlapped with the first steel sheet, and the average heating rates V and v1 satisfy Expressions (1) to (3), and the heating is performed at a heating temperature and for a heating time within a specific range on a plane of coordinates defined by the heating time and the heating temperature.