The invention relates to a device for controlling the deployment of an inflatable structure including, in the non-deployed state, a flexible tube (12) which is folded in zigzags and fixed to one end of a plug (13) provided with a buoyant gas admission (15), the other end of the tube being closed; means (25 to 29) for controlling the change of state of the tube from the folded state (12a) to the deployed state (30), the means being arranged inside the tube (12) and consisting of a set of interconnected flexible blades (25) which are radially arranged around the strut (16) in the form of petals, in such a way that the set can be displayed along the strut; and means (28, 29) for bringing the set of petals (25) towards the plug (13) in such a way as to press the folded part (12a) of the tube, each petal (25) being applied to a series of superimposed folds (21 to 24) of the folded part of the tube.