The present invention provides a square rotary joint, which mainly comprises a square body and a pivoting body, wherein the square body is internally disposed with a channel, and each of the two sides of the square body is disposed with a first connecting portion and a second connecting portion respectively. The first connecting portion and the second connecting portion are connected to the channel, the square body is disposed with a pivoting portion on one side thereof, and the pivoting portion is in communication with the channel. The pivoting body is mutually pivoted with the pivoting portion and is in communication with the channel, one end of the pivoting body is configured to introduce a gas into the channel, so that the gas can be introduced to the first connecting portion and the second connecting portion. Therefore, the present invention provides a rotary joint which is easy to install and is able to reduce occupied space, thereby reducing the number of the operation in process and the space occupied by the paper-pulp molding platform.