To provide a shelf positioning device for pipe rack, which is promptly attached to an erecting pipe of a pipe rack, can position a net shelf or a pipe, and is easily manufactured having good structure.

The main body of a ferrule sheet fixed to a net shelf or a horizontal pipe and a pivotal member pivotally equipped on the main body of the ferrule sheet are included, the open ferrule is connected with the tail end of the main body of the ferrule, a shaft equipped on the ferrule is passed through a pair of long holes on the pivotal member, and the pivotal member is made rotatable and moved forward and rearward. A closed port is connected to a front part of the pivotal member to the main body of the ferrule sheet. A closed part is connected to the front end of the pivotal member, a dovetail shape projection is equipped on the front end of the closed port and a dovetail groove is formed on the front end of the open ferrule corresponding to the dovetail shape projection. The ferrule formed by connecting both surrounds the outside of a cramp piece of the erected pipe to rapidly position the net shelf or the pipe.