Abstract: The present invention provides an automatic control device of foldable tent connecting to several roof strut sets wherein, said control device is of a central standing base containing a sliding hub, a spring and a tappet roller at inside. Cooperating to an extra force exerting on the central standing base to press it down relative to the roof strut sets, the sliding hub brings the tappet roller continuously to go down and up, by means of the special design between the spring and all the pushing lugs and hook slots of the tappet roller, positioning the sliding hub with the locking pin of the central standing base can be carried out, so that the tent can be opened and kept in open configuration automatically; when repeatedly press down the central standing base relative to the roof strut sets, the tent can be closed.