We investigated the effect of In atoms in p-GaN on the damage induced by electron cyclotron resonance etching. After etching the surface of p-GaN without In atoms, the I-V characteristics between two Ni/Au electrodes on the surface showed non-Ohmic behavior. This is ascribed to the damage induced by this etching process, as previously reported. The Ohmic characteristics were much improved for p-GaN doped with In atoms compared with those for p-GaN without In atoms. The Ohmic characteristics were improved as the In mole fraction in the p-(In)GaN was increased. The non-Ohmic behavior arises from the damaged layer between the Ni/Au electrode and the p-(In)GaN layer. This damaged layer is considered to become thinner as the In mole fraction is increased, resulting in improved Ohmic characteristics.