Abstract: An apparatus and method is provided for use on the pickup head of an optical disc drive for the purpose of adjusting the pickup head to the optimal focus point through a featured tree-structured search algorithm. The apparatus and method can perform the adjustment automatically so as to eliminate the need to use laborious work to make the adjustment in manufacture. The apparatus is activated each time the optical disc drive is started so as to offset the unbalanced condition in the focusing error signal, which allows the optical disc drive to perform the access operation more reliably. Moreover, the apparatus is realized in a digital manner that allows easy implementation and a low manufacturing cost.