A nitride semiconductor laser including a laminate that includes an n-side semiconductor layer, an active layer and a p-side semiconductor layer, the n-side semiconductor layer or p-side semiconductor layer including a current blocking layer 30 that is made of InxAlyGa1-x-yN and has a stripe-shaped window 32 formed therein to pass current flow. The thermal displacement of the magnetic head is compensated by operating micro actuators on the load beam in accordance with the temperature rise of the IC which is measured by a temperature sensor. When this setting range does not agree with the cell unit of the current cell, the current cell is divided to set a sequence of divided cells.