PURPOSE: To make synchronous follow-up control even when the object to be followed is apart from the follower by sensing the relative speed of the two by the use of a contactless sensing means such as photo-sensor.

CONSTITUTION: No.1 and No.2 photo-sensors A, B are installed, at a distance slightly smaller than the length l of the subject to be followed 1 seen in its traveling direction, on a follower 2 so arranged as to move in parallel with the path along which the object 1 travels as in the direction shown by the arrow, and a photo-followup start command device C is provided on the upper stream of the follower 2 about its followup start position. Sensors AWC are composed of phot-couplers 4aW4c, respectively, and when the object 1 has attained the Position W to actuate emission of the "1" signal from the photo-coupler 4c, an accelerative integral signal Ea is generated to increase the speed of the object 2 with a constant acceleration. When the sensor A senses the object 1 on the way of acceleration (Position X), a decelerative integral signal Er is generated. At Position Y, the accelerative and decelerative controls are stopped.