Abstract: Apparatus for measuring level and quantity of fuel oil stored in a tank, which comprises a pair of electrodes, one being a number of segmented electrodes while the other is an elongated electrode to form a number of capacitors, a source for applying high frequency voltage to said electrodes one by one to generate electric signals, means for converting said signals to corresponding high frequency signals, means for computing height of said liquid level from frequencies of signals, and means for computing the fuel quantity. Said capacitor probe is prepared by fastening an elongated flexible substrate IS printed with said electrodes round a rigid bar S, covering the outer surface thereof with insulative material, and fitting a metallic tube. Said segmented electrodes are arranged lengthwise in two rows in zig-zagged and partly overlapped.