An optical touch apparatus including a first light emitting device, a second light emitting device, a third light emitting device, a fourth light emitting device, a first image detector, a second image detector, and a control unit is provided. The control unit controls the average brightness of the third light emitting device less than each of the average brightness of the second light emitting device and the fourth light emitting device when the control unit controls the first image detector to detect an image. The control unit controls the average brightness of the second light emitting device less than each of the average brightness of the first light emitting device and the third light emitting device when the control unit controls the second image detector to detect an image. A driving method is also provided.