Abstract: A level detector includes a level detecting capacitor, an oscillating circuit, and an amplifying circuit. The level detecting capacitor includes a pair of continuously extended electrodes separated by a predetermined distance and disposed at a predetermined position in a container adapted for accommodating a dielectric fluid having levels which are to be detected therein. The oscillating circuit is adapted to apply an alternating voltage of a constant frequency to the level detecting capacitor by way of an impedance element adapted to provide signal voltages. The amplifying circuit is adapted to amplify voltage drops at the impedance element so as to output a signal corresponding to the level of the dielectric fluid. Thus, the level detector can output signal voltages of high linearity and dependant on the fluid level variations using a simple circuit arrangement.