In the production of cups or containers by conventional deep drawing, the limiting drawing ratio obtained during the first drawing is very minimal. Therefore, to make deep cups, redrawing or ironing in one or more subsequent stages is necessary. An innovative method of producing very deep cups by employing a developed blank was previously proposed. In this method, the drawing resistance of the blank is reduced drastically, and so deep cups can be obtained at the first drawing. However, the drawn cup has seams in the side wall. To make an airtight cup, the seams must be joined. In this study, a new method of forming deep cups by using the developed blank was investigated. The developed blank is drawn with a punch, and friction stir welding (FSW) is conducted simultaneously to join the seams formed in the side wall. A rotation probe is put on the flange contact point and friction heat is generated, thus joining the seam parts. The experimental results show that the production of a very deep and airtight cup in a single process can be successfully accomplished with this proposed method.