A tracking servo system in a recordable optical disk player apparatus utilizes clock signals to be produced by irradiating laser beam to clock pits in servo areas as a reference signal for on-track adjustment. Based on the clock signal, polarity of a tracking error signal is detected for selectively opening and closing servo loop of the tracking servo system. CLOSED LOOP on-track adjustment will be performed while a laser beam spot is in a range where the tracking error indicative value is gradually reduced according to decreasing of the distance of the laser beam spot to the track center. On the other hand, OPEN LOOP on-track adjustment will be performed while the laser beam spot is in a range where the tracking error indicative value is increased according to decreasing of the distance between the laser beam spot and the track center. Since the polarity of the tracking error signal may indicate the range of the laser beam spot position, selection of the CLOSED LOOP and OPEN LOOP can be made without requiring the signal to be reproduced from the data area. :