The present invention relates to the method for soldering the interconnector to the photovoltaic cell, in manufacturing the photovoltaic module, which makes it possible to significantly inhibit or almost eliminate the deformation of the photovoltaic cell due to heat of the soldering when soldering the interconnector (hereinafter, refer also to as “lead wire”) to the photovoltaic cell (hereinafter, refer simply to as “cell”) that forms the module. In the present invention, the interconnector positioned at the predetermined position of the photovoltaic cell is soldered by dissolving the solder. As the photovoltaic cell is entirely being heated under the heating atmosphere, the photovoltaic cell is cooled down slowly thereafter. In the present invention, even if the photovoltaic cell is thin, similar heating does not warp the photovoltaic cell.