PURPOSE: To always maintain horizontal balance of left and right optical systems by detecting inclination between left and right optical systems using a gyro and correcting positions of left and right optical systems using the information.

CONSTITUTION: When a steroscopic video image pickup device is placed in a horizontally unbalanced state in the left and right direction, the direction and amount of inclination are detected by an inclination detector 4, and a horizontal balance correction signal calculated by a central processing unit 11 basing on the data is inputted to a left and right horizontal balance correcting circuit 12 to operate a servo driving device 18. By driving a base frame in the direction opposite to detected inclination by the same amount of inclination, horizontal balance of the base frame in left and right direction is maintained. When the three-dimensional video image pickup device is placed in a horizontally unbalanced state in the before and behind direction, a longitudinal horizontal balance correcting circuit 13 is operated similarly, and by driving the base frame by a servo driving device 19 in the direction opposite to detected inclination by the same amount of inclination, longitudinal horizontal balanced of a base frame in the before and behind direction can be maintained.