Device (1; 100) for soft closing an opening element on a support element, said support element comprising: - a wall; - a first bore and a second bore passing through said wall, said second bore having a first edge and a second edge facing the first edge; said device (1; 100) comprising: - a stop body comprising means (31, 32) for locking the opening element; and - a fastening plate comprising: - a base intended to be supported on the outer face of the wall; - a first attachment member intended to be inserted into the first bore of the support element; and - a second attachment member intended to be inserted into a second bore of the support element, said second attachment member being aligned with the first attachment member along a longitudinal axis of the device (1; 100); the soft closing device comprising a latch having a stop member, said latch being connected to the base by a first elastic spring hinge having an axis; the soft closing device being characterized in that the latch is rotatably movable relative to the base between: - a locked rest position in which the stop member abuts against the second attachment member so as to form a block comprising a first face intended to be supported against the first edge of the second bore and a second face intended to be supported against the second edge of the second bore, and - an unlocked stressed position in which the stop member is offset relative to the second attachment element, so that, owing to the first elastic hinge connecting the latch to the plate, the latch returns to its initial position and thus to the locked position, the stop member being automatically placed in a position of locking the first attachment member by the spring effect of the latch provided by the first elastic hinge. - a wall; - a first bore and a second bore passing through said wall, said second bore having a first edge and a second edge facing the first edge; said device (1; 100) comprising: - a stop body comprising means (31, 32) for locking the opening element; and - a fastening plate comprising: - a base intended to be supported on the outer face of the wall; - a first attachment member intended to be inserted into the first bore of the support element; and - a second attachment member intended to be inserted into a second bore of the support element, said second attachment member being aligned with the first attachment member along a longitudinal axis of the device (1; 100); the soft closing device comprising a latch having a stop member, said latch being connected to the base by a first elastic spring hinge having an axis; the soft closing device being characterized in that the latch is rotatably movable relative to the base between: said device (1; 100) comprising: - a stop body comprising means (31, 32) for locking the opening element; and - a fastening plate comprising: - a base intended to be supported on the outer face of the wall; - a first attachment member intended to be inserted into the first bore of the support element; and - a second attachment member intended to be inserted into a second bore of the support element, said second attachment member being aligned with the first attachment member along a longitudinal axis of the device (1; 100); - a stop body comprising means (31, 32) for locking the opening element; and - a fastening plate comprising: - a base intended to be supported on the outer face of the wall; - a first attachment member intended to be inserted into the first bore of the support element; and - a second attachment member intended to be inserted into a second bore of the support element, said second attachment member being aligned with the first attachment member along a longitudinal axis of the device (1; 100); the soft closing device comprising a latch having a stop member, said latch being connected to the base by a first elastic spring hinge having an axis; the soft closing device being characterized in that the latch is rotatably movable relative to the base between: - a locked rest position in which the stop member abuts against the second attachment member so as to form a block comprising a first face intended to be supported against the first edge of the second bore and a second face intended to be supported against the second edge of the second bore, and - an unlocked stressed position in which the stop member is offset relative to the second attachment element, so that, owing to the first elastic hinge connecting the latch to the plate, the latch returns to its initial position and thus to the locked position, the stop member being automatically placed in a position of locking the first attachment member by the spring effect of the latch provided by the first elastic hinge.