The invention relates to a closure device comprising a closure wall having a communication conduit passing through it and intended to close the opening of a container of a product and a stopper movable in the duct. The stopper comprises a cavity open on one side of the wall, closed by a bottom and comprising at least one lateral opening. In the closed position, this bottom closes the conduit, and in the open position, the side opening(s) and said bottom exit the conduit, the conduit thus being open in fluid communication through the stopper. The invention also relates to a product refill comprising a container closed by this closure device. It also relates to a dispensing device comprising this refill and a dispensing head.