A substrate 1 for growing nitride semiconductor has a first and second face and has a thermal expansion coefficient that is larger than that of the nitride semiconductor. At least n-type nitride semiconductor layers 3 to 5, an active layer 6 and p-type nitride semiconductor layers 7 to 8 are laminated to form a stack of nitride semiconductor on the first face of the substrate 1. A first bonding layer including more than one metal layer is formed on the p-type nitride semiconductor layer 8. A supporting substrate having a first and second face has a thermal expansion coefficient that is larger than that of the nitride semiconductor and is equal or smaller than that of the substrate 1 for growing nitride semiconductor. A second bonding layer including more than one metal layer is formed on the first face of the supporting substrate. The first bonding layer 9 and the second bonding layer 11 are faced with each other and, then, pressed with heat to bond together. After that, the substrate 1 for growing nitride semiconductor is removed from the stack of nitride semiconductor so that a nitride semiconductor device is provided.