A solar tracker comprises: a measuring section which measures the quantity of electric power generated by a solar panel; a solar position getting section which gets information about the theoretical solar position; a driving section which changes the orientation of the solar panel; a dither control section which measures a solar position; a positional shift measuring section which measures a solar positional shift between the measured solar position and the theoretical solar position. The driving section corrects the theoretical solar position based on the estimated attitude error and controls the orientation of the solar panel based on the theoretical position corrected.