<p>A temperature sensor includes a capacitor having electrodes between which a dielectric body having its dielectric constant variable depending on the variations of ambient temperature is interposed, and a CR oscillating circuit utilizing the capacitor. The dielectric body is made of a ceramic dielectric material which has a working temperature range in the normal dielectric phase with the dielectric constant thereof having a temperature coefficient ranged betwen -1,000 ppm and -10,000 ppm. The ceramic dielectric body is also used as a substrate on which the CR oscillating circuit is formed.</p>
