Change in electronic structure by lithium ion deintercalation in LiNiO2 was investigated by Ni L-edge and O K-edge X-ray absorption near edge structure (XANES). The Ni L-edge XANES for LiNiO2 indicated the Ni occurs in LiNiO2 as Ni2+ ions. The Ni L-edge XANES for Li x NiO2 showed no chemical shift to indicate that the Ni ion in Li x NiO2 is still Ni2+, even at low x value. The O K-edge XANES for Li x NiO2 also indicated that the holes compensating the lithium ion deintercalation are located primarily in oxygen 2p states rather than in Ni 3d states.