The present invention provides a thin film magnetic head in which a magnetic domain structure of a magnetic pole layer is controlled and fluctuation in recording magnetization caused by leaked magnetic flux generated by unintentional shift of a magnetic domain wall can be prevented. When a length of a front end portion of a magnetic pole part layer, which specifies a recording track width of a recording medium, is set as D, and a width of an upper edge of a magnetic pole end surface, positioned on a medium outflow side, is set as W, a dimensional ratio D/W of the length D to the width W is set so as to lie within the range of 0