PURPOSE: To provide higher accuracy in positioning and higher stability of a product and to enable unmanned adjusting operation by positioning automatically video heads according to a prescribed program.

CONSTITUTION: A base 13 on which a head drum 1 provided with the video heads 2A, 2B facing each other, a drum clamping mechanism 14 which has a tapered part 18 butting against the shaft hole 1A of the drum 1, cameras 22A, 22B which pick up the respective images of the video heads, a stage 25 which is rotated by each slight angle by a motor 26, a cam 27 which adjusts the position of the video heads by the rotation of the output shaft 52A thereof and a control device which executes the prescribed program are provided. The control device runs the motor 26 to the position where the other head gap coincides with the head gap of the video head picked up by one camera as a reference. The control device positions the video heads by the cam 27 during this time. The video heads are thus automatically positioned according to the prescribed program.