Ni oxide thin films with thermal sensitivity superior to Pt and Ni thin films were formed through annealing treatment after Ni thin films were deposited by a r.f. magnetron sputtering method. Resistivity values of Ni oxide thin films were in the range of $10.5{mu}{Omega}cm$ to $2.84{ imes}10^{4}{mu}{Omega}cm$ according to the degree of Ni oxidation. Also temperature coefficient of resistance(TCR) values of Ni oxide thin films depended on the degree of Ni oxidation from 2,188 ppm/$^{circ}C$ to 5,630 ppm/$^{circ}C$ in the temperature range of $0{sim}150^{circ}C$. Because of the high linear TCR and resistivity characteristics, Ni oxide thin films exhibit much higher sensitivity to flow and temperature changes than pure Ni thin films and Pt thin films.