Disclosed is a DC voltage conversion circuit of a liquid crystal display apparatus, including: a main pumping circuit including a plurality of thin film transistors and configured to output voltage for driving a liquid crystal display apparatus when the plurality of thin film transistors are alternately turned on or off; and a switch control signal generator configured to control voltages applied to gates of the plurality of thin film transistors by inversion of a clock signal, in which each thin film transistor is turned on when positive gate-source voltage is applied thereto, and turned off when negative gate-source voltage is applied thereto.