A thin film magnetic head capable of preventing unintentional erasing of information during non-recording, ensuring its magnetic operating characteristics with stability. A top read shield layer extends rearward relative to a back gap (or a back-gap rear-end position), and a write shield layer also extends rearward relative to the back gap. Thus, a stray external magnetic field generated from a voice coil motor or the like is more likely to be taken in by not only the top read shield layer but also the write shield layer; the stray external magnetic field is less likely to converge on the top read shield layer. This reduces the likelihood of an undesired magnetic closed loop being formed between the top read shield layer and magnetic pole layer and a recording medium, and thus reduces the likelihood of unintentional overwriting of information taking place during non-recording due to the undesired magnetic closed loop.