A transfer conveyor which prevents collisions between works to be conveyed when the works to be conveyed or stored are carried on a conveyer track by a work support having a length shorter than the length of works to be conveyed, which permits reverse traveling during maintenance operations and the like. The collision preventing mechanism includes a sensing element which is biased into a contact position where it engages a leading work support on the conveyor track and is deflected, a sensing lever 132, which mounts the sensing element and pivots in accordance with the contacting/deflecting operation of the sensing element, and a stopper lever downstream from the sensing element, which is connected to the sensing element to be displaced into the path of travel of the next trailing work support when the sensing element is in the contacting position, The stopper lever limits the travel of the trailing work support to a predetermined storage conveying interval.