This paper describes a new seam welding technique for aluminum sheets and its experimental results. When an impulse current from an energy-stored capacitor bank passes through a flat one-turn coil, a high-density magnetic flux is suddenly generated in the coil. Eddy currents are induced inside the overlapped ends of two aluminum sheets (thickness 1.0 mm each) with a gap placed in the coil. The two sheets are suddenly pressed together by magnetic pressure applied onto them. If the moving velocity of the sheets is high, the both surfaces are cleared by an effect of the collision which is known as explosive welding, and then can be joined both by the magnetic pressure onto them and by the joule heat generated in them. A bank energy required for this impact seam welding of an area 5 x 50 mm(2) is less than 1 kJ.