An organic light emitting diode display device includes: an organic light emitting diode; a driving transistor having a first electrode, a second electrode, and a third electrode, the first electrode coupled to the variable driving voltage source and controlling the operation of the organic light emitting diode depending on a voltage difference between the third electrode and the second electrode; a first current source for supplying a first current to the third electrode and the second electrode of the driving transistor through a data line; a second current source for supplying a second current to the third electrode and the second electrode of the driving transistor through the data line; and a digital-to-analog converter for detecting the level of a sensing current flowing between the first and second electrodes of the driving transistor through the data line.