A magnetic head inspection device inspects the write track width of a thin film magnetic head in a phase as early as possible during the manufacturing process. A recording signal (excitation signal) is input from bonding pads to the thin film magnetic head in a rowbar, and the magnetic field generated by the write pole (element) included in the thin film magnetic head is observed directly by using a magnetic force microscope (MFM), a scanning Hall probe microscope (SHPM), or a scanning magneto resistance effect microscope (SMRM) that performs a scanning motion at a position equivalent to the flying height of the magnetic head. In this manner, a shape of the generated magnetic field instead of the physical shape of the write pole (element) is measured; thus, a non-destructive inspection can be performed on the effective magnetic track width.