A method of manufacturing an air flow type thin film magnetic head includes the steps of providing a slider for a thin film magnetic head; forming a photo-sensitive layer directly on the slider: subjecting the photo-sensitive layer to a light beam having controlled loci to form a desired pattern on the photo-sensitive layer, their: loci of the light beam corresponding to configuration of rails to be formed on a surface of the slider; and forming the rails in accordance with the desired pattern. The loci of the light beam is controlled by a data processor. Various rail patterns including an asymmetrical and non-parallel rail pattern can be easily formed on a slider of a magnetic head.