In a method of forming a track width defining layer including a magnetic pole portion, a base film is initially formed on a write gap layer. The base film includes a first layer made of a magnetic material having a saturation magnetic flux density of 1.8 T or more, and a second layer formed on the first layer and made of a magnetic material. The magnetic material forming the second layer is a material containing Fe or Ni as a main component and without containing Co. Then, a frame having an opening of a shape matching with the track width defining layer is formed on the second layer. Subsequently, the track width defining layer is formed within the opening by electroplating, using the base film as an electrode.