To provide a conveyer with high working efficiency in adjusting the width between both conveying guide rails.

The conveyer has a pair of conveying guide rails 24 faced so as to freely approach or release each other and supports a conveying substance between the conveying guide rails 24 for conveying. One conveying guide rail 24 is supported to the frame part supporting the conveying guide rails 24 so as to freely approach or release in the other conveying guide rail direction. A positioning guide body 28 long in the approaching or releasing direction is installed in the frame part, and plural positioning recessed parts 28a are installed in the approaching or releasing direction on one side surface of the positioning guide body 28. A ball plunger body 31 having a locking ball 31c to be selectively, detachably, elastically-locked to each positioning recessed part 28a when one conveying guide rail 24 is moved in the approaching or releasing direction is installed in the conveying guide rail 24.