A magnetic recording/reproducing head assembly comprising a first magnetic path forming member on which a coil is mounted, a second magnetic path forming member which forms a magnetic path in cooperation with the first magnetic path forming member, and a film laminate formed at a front gap portion between the first magnetic path forming member and the second magnetic path forming member. The film laminate includes a magnetic detecting element for detecting a change in a magnetic field and a soft magnetic film or films. This magnetic head assembly is prepared by forming the film laminate on a head base of the head assembly, bonding a core member to the head base with the film laminate formed thereon, and mounting a coil on the core member.