An organic light emitting display device, comprising: pixels connected to scan lines and data lines; and a scan driver, wherein each pixel, comprises: a first transistor (M1; M1'; M11; M21; M31) disposed on a current path from a first driving power supply (ELVDD) to a second driving power supply (ELVSS) via an organic light emitting diode (OLED); and a further transistor (M2; M2'; M13; M22; M33) and an auxiliary transistor (MS; M11; MS21; MS31) serially connected on a leakage current path which is different from the current path, wherein the scan driver is configured to supply scan signals to the scan lines such that the further transistor (M2; M2'; M13; M22; M33) and the auxiliary transistor (MS; M11; MS21; MS31) have an overlapping turn-on period where the further transistor (M2; M2'; M13; M22; M33) is configured to be turned off before the auxiliary transistor (MS; M11; MS21; MS31) is turned off, wherein the further transistor (M2; M2'; M13; M22; M33) is connected between a gate electrode of the first transistor (M1; M1'; M11; M21; M31) and the auxiliary transistor (MS; M11; MS21; MS31), characterized in that the further transistor (M2; M2'; M13; M22; M33) is formed of a polysilicon semiconductor transistor, and the auxiliary transistor (MS; M11; MS21; MS31) is formed of an oxide semiconductor transistor. pixels connected to scan lines and data lines; and a scan driver, wherein each pixel, comprises: a first transistor (M1; M1'; M11; M21; M31) disposed on a current path from a first driving power supply (ELVDD) to a second driving power supply (ELVSS) via an organic light emitting diode (OLED); and a further transistor (M2; M2'; M13; M22; M33) and an auxiliary transistor (MS; M11; MS21; MS31) serially connected on a leakage current path which is different from the current path, wherein the scan driver is configured to supply scan signals to the scan lines such that the further transistor (M2; M2'; M13; M22; M33) and the auxiliary transistor (MS; M11; MS21; MS31) have an overlapping turn-on period where the further transistor (M2; M2'; M13; M22; M33) is configured to be turned off before the auxiliary transistor (MS; M11; MS21; MS31) is turned off, wherein the further transistor (M2; M2'; M13; M22; M33) is connected between a gate electrode of the first transistor (M1; M1'; M11; M21; M31) and the auxiliary transistor (MS; M11; MS21; MS31), characterized in that the further transistor (M2; M2'; M13; M22; M33) is formed of a polysilicon semiconductor transistor, and the auxiliary transistor (MS; M11; MS21; MS31) is formed of an oxide semiconductor transistor. a first transistor (M1; M1'; M11; M21; M31) disposed on a current path from a first driving power supply (ELVDD) to a second driving power supply (ELVSS) via an organic light emitting diode (OLED); and a further transistor (M2; M2'; M13; M22; M33) and an auxiliary transistor (MS; M11; MS21; MS31) serially connected on a leakage current path which is different from the current path, wherein the scan driver is configured to supply scan signals to the scan lines such that the further transistor (M2; M2'; M13; M22; M33) and the auxiliary transistor (MS; M11; MS21; MS31) have an overlapping turn-on period where the further transistor (M2; M2'; M13; M22; M33) is configured to be turned off before the auxiliary transistor (MS; M11; MS21; MS31) is turned off, wherein the further transistor (M2; M2'; M13; M22; M33) is connected between a gate electrode of the first transistor (M1; M1'; M11; M21; M31) and the auxiliary transistor (MS; M11; MS21; MS31), characterized in that the further transistor (M2; M2'; M13; M22; M33) is formed of a polysilicon semiconductor transistor, and the auxiliary transistor (MS; M11; MS21; MS31) is formed of an oxide semiconductor transistor.