A sensing circuit that operates even at a low power supply voltage and reduces stress on a memory cell in a flash memory device without lowering a reading speed at the low power supply voltage is provided. The sensing circuit includes a first load element, a first inverting circuit, a second load element, a second inverting circuit, and a sense amplifier. The first load element includes an end connected with a bit line of a main cell array within the flash memory device. The first inverting circuit includes an input terminal connected with the bit line of the main cell array and an output terminal connected with another end of the first load element. The second load element includes an end connected with a bit line of a reference cell array within the flash memory device. The second inverting circuit includes an input terminal connected with the bit line of the reference cell array and an output terminal connected with another end of the second load element. The sense amplifier compares a voltage of the bit line of the main cell array with a voltage of the bit line of the reference cell array and generates an output signal according to a result of the comparison.