A ballast type detecting circuit includes a ballast signal clamping circuit coupled to a ballast, wherein the ballast signal clamping unit is configured to clamp an output of the ballast, and a ballast type detection circuit configured to compare first and second reference clocks and the clamped output of the ballast to determine a type of the ballast, each of the first and second reference clocks having a frequency lower than an output frequency of a first type ballast and higher than an output frequency of a second type ballast. Thus, the ballast type detecting circuit detects a type of electronic ballast and magnetic ballast based on a digital output signal and decreases a number of outside circuit elements through a ballast type detection based on a digital output signal.