The differential type level indicator cum controller is used for measurement of difference of two liquid levels. The level is detected by capacitance principle. The capacitance is formed between the active electrode (flexible Teflon taped wire) and the reference wire. As the liquid level rises(or falls) the capacitance between the active electrode and reference increases(or decreases) which is converted into equivalent signal. The output of two probe unit is fed to the controller unit to display the difference in level and operate alarm output at any desired differential level.