In a gamma voltage generator and gamma voltage generating method that can tune the gamma voltages individually, several gamma currents of a same magnitude are generated for each to flow through a variable resistive element to generate a variable common voltage and several variable voltages, from which a common gamma voltage and several first gamma voltages are generated. By use of the symmetric property of the gamma curve corresponding to those gamma voltages to be generated, several voltages are generated by mapping the first gamma voltages with the common gamma voltage as the center axis, and from which several second gamma voltages are derived. The common gamma voltage and the first and second gamma voltages are provided for those gamma voltages corresponding to the gamma curve.