A recording head of a disk device includes a main magnetic pole, a write shield which faces the main magnetic pole with a write gap interposed therebetween, a coil configured to generate a magnetic field in the main magnetic pole, and a spin torque oscillator which is arranged in the write gap. The spin torque oscillator includes an intermediate layer formed on the main magnetic pole, a field generation layer formed on the intermediate layer, a spin injection layer, and an interface magnetic layer. The field generation layer and the spin injection layer are arranged in parallel to each other in the direction which intersects with the gap length direction of the write gap, and the spin injection layer is electrically connected with the write shield.