PURPOSE: To output only accurate audio data regardless of the mounting accuracy and the tracking state of each CCD line sensor.

CONSTITUTION: The 1st to 3rd CCD line sensors 2 to 4 are provided so that the read areas of the CCD line sensors 2 to 4 may be respectively positioned in the width of the recording track of the audio data recorded in the digital sound track of a motion picture film 1; and 1st to 3rd tracking detection circuits 5 to 7 detect the tracking state based on the audio data read by the CCD line sensors 2 to 4. Then, a switching control circuit 8 controls to switch a changeover switch 9 by which the audio data from the CCD line sensors 2 to 4 is supplied based on detection output from the detection circuits 5 to 7 so that only the audio data reproduced in the accurate tracking state may be outputted.