A positive coefficient thin-film thermistor which comprises a thin film exhibiting a PTC characteristic and having a thickness of 0.005 to 5 .mu. m and electrodes as constituting elements, and wherein the thin film is composed of a barium titanate based composition and the PTC characteristic is represented by a resistnace variation in transition region of 1 - 10 orders of magnitude and a maximum resistance temperature variation rate of 1 - 20 order/ .degree.C.
