An electromagnetic fuel injection valve is provided, which allows the amount of lift to be adjusted and established following the assembly of the nozzle assembly so that it is suitable for high pressure cylinder injection of fuel and which also allows the amount of lift to be established with high precision. A method for assembling the nozzle assembly is also offered. This invention comprises a thin-walled skirt portion formed in a protruding manner at the nozzle holder, a valve seat that is introduced under pressure to the skirt portion, with the valve seat and the nozzle holder welded and joined at the skirt portion, and, preferably, the application of a load from the outside of the nozzle holder following welding to bring about the irreversible deformation of the nozzle holder and establish the final amount of lift.