A magnetic head for tape recording and/or reproducing is composed of a pair of abutting thin magnetic metal cores with front and back gaps therebetween, and a pair of magnetic oxide cores sandwiching each of the magnetic metal cores therebetween. The magnetic oxide cores include bodies of glass disposed adjacent the front gap and sandwiching each magnetic metal core to allow the front gap to be visually checked for its depth. To fabricate such a magnetic head, magnetic oxide cores are bonded to a thin magnetic metal core, and the bonded block is cut off across the magnetic metal core to form two block pieces. Each of the block pieces is provided with bodies of glass in recesses formed in a cut surface thereof. After the cut surfaces have been ground, the block pieces are bonded with the cut surfaces confronting each other while keeping the magnetic metal cores in alignment. The bonded block pieces are cut off along the aligned magnetic metal cores into a magnetic head blank, which is then ground to provide a tape-contacting surface.