The present invention discloses a voltage level generating device. The voltage level generating device includes: a reference voltage generating module, a first circuit module, a second circuit module, and a switch module. The voltage level generating device disclosed in the present invention only requires a buffer, a voltage regulator, and a arithmetic logic unit (ALU) to attain the same function of the conventional common voltage level generating device, and thus the circuit layout area can be reduced so as to decrease the cost of the integrated circuit (IC). In addition, the voltage level generating device disclosed in the present invention also can select different output of voltage level in order to reduce the power consumption of a display device.