Connecting device for connecting a supporting shore to a formwork structure defining a formwork plane, comprising: - a first part, designed to be fixed to the formwork structure and comprising a plug-in housing extending in a first direction (I-I) intended to be oriented substantially perpendicular to the formwork plane, - a second part, designed to be fixed to the supporting shore, and comprising a plug-in portion which extends in a second direction (II-II) between a proximal end and a distal end, which is equipped with a lateral surface, and which is designed to be articulated to the first part in pivoting about a third direction (III-III) substantially perpendicular to the first direction (I-I), characterized in that: - the third direction (III-III) is defined by a pivot pin formed by the first part, while the plug-in portion comprises an oblong slot which extends in the second direction (II-II) between a first end and a second end and which is able to accept the pivot pin, - in an assembled state, the second part is able to be moved with respect to the first part between at least three positions, namely: • a plugged-in position in which the plug-in portion is accepted by push-fitting into the plug-in housing, the pivot pin being engaged in the oblong slot and away from the first end of the oblong slot in the second direction (II-II), the first (I-I) and second (II-II) directions being parallel to one another, • a withdrawn position in which the plug-in portion is arranged out of the plug-in housing, the first (I-I) and second (II-II) directions being parallel to one another, and the pivot pin being engaged in the oblong slot at the first end of the oblong slot so as to allow the second part to pivot about the pivot pin, • a retracted position, in which the plug-in portion is pivoted so that the second direction (II-II) is angularly separated from the first direction (I-I), in which the pivot pin is engaged in the oblong slot away from the first end of the oblong slot, the plug-in portion therefore bearing via its lateral surface against a lower edge of a lateral wall of the plug-in housing, to oppose the pivoting of the second part towards the first direction (I-I). - a first part, designed to be fixed to the formwork structure and comprising a plug-in housing extending in a first direction (I-I) intended to be oriented substantially perpendicular to the formwork plane, - a second part, designed to be fixed to the supporting shore, and comprising a plug-in portion which extends in a second direction (II-II) between a proximal end and a distal end, which is equipped with a lateral surface, and which is designed to be articulated to the first part in pivoting about a third direction (III-III) substantially perpendicular to the first direction (I-I), - the third direction (III-III) is defined by a pivot pin formed by the first part, while the plug-in portion comprises an oblong slot which extends in the second direction (II-II) between a first end and a second end and which is able to accept the pivot pin, - in an assembled state, the second part is able to be moved with respect to the first part between at least three positions, namely: • a plugged-in position in which the plug-in portion is accepted by push-fitting into the plug-in housing, the pivot pin being engaged in the oblong slot and away from the first end of the oblong slot in the second direction (II-II), the first (I-I) and second (II-II) directions being parallel to one another, • a withdrawn position in which the plug-in portion is arranged out of the plug-in housing, the first (I-I) and second (II-II) directions being parallel to one another, and the pivot pin being engaged in the oblong slot at the first end of the oblong slot so as to allow the second part to pivot about the pivot pin, • a retracted position, in which the plug-in portion is pivoted so that the second direction (II-II) is angularly separated from the first direction (I-I), in which the pivot pin is engaged in the oblong slot away from the first end of the oblong slot, the plug-in portion therefore bearing via its lateral surface against a lower edge of a lateral wall of the plug-in housing, to oppose the pivoting of the second part towards the first direction (I-I). • a plugged-in position in which the plug-in portion is accepted by push-fitting into the plug-in housing, the pivot pin being engaged in the oblong slot and away from the first end of the oblong slot in the second direction (II-II), the first (I-I) and second (II-II) directions being parallel to one another, • a withdrawn position in which the plug-in portion is arranged out of the plug-in housing, the first (I-I) and second (II-II) directions being parallel to one another, and the pivot pin being engaged in the oblong slot at the first end of the oblong slot so as to allow the second part to pivot about the pivot pin, • a retracted position, in which the plug-in portion is pivoted so that the second direction (II-II) is angularly separated from the first direction (I-I), in which the pivot pin is engaged in the oblong slot away from the first end of the oblong slot, the plug-in portion therefore bearing via its lateral surface against a lower edge of a lateral wall of the plug-in housing, to oppose the pivoting of the second part towards the first direction (I-I).